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corona-warn-app / cwa-app-android

Native Android app using the Apple/Google exposure notification API. The CWA development ends on May 31, 2023. You still can warn other users until April 30, 2023. More information:
https://coronawarn.app/en/faq/#ramp_down
Apache License 2.0
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paper QR Code not readable #3514

Closed Timo1993 closed 2 years ago

Timo1993 commented 3 years ago

Hi, I got a digital certificate. When I tried to scan a QR code, it is not detected. I used a Xiaomi Redmi Note 9. The most recent app from the play store is installed. I tried it about 50 times, but it is not detected. The code itself is detected with another QR code scanner.

Internal Tracking ID: EXPOSUREAPP-8028 Internal Tracking ID: EXPOSUREAPP-10502

Ein-Tim commented 3 years ago

@Timo1993 Does the CovPass App recognize the code?

Timo1993 commented 3 years ago

@Timo1993 Does the CovPass App recognize the code?

No, the code is also not recognized by the CovPass app. But when I use a QR code scanner app, I can read it.

Ein-Tim commented 3 years ago

@Timo1993

Are you sure that the QR-Code is a EU Digital Covid Certificate?

A QR-Code for this is printed on such a sheet of paper: image

(Picture from https://www.coronawarn.app/en/faq/#vac_cert_invalid)

Timo1993 commented 3 years ago

Yes, I have exactly this document and it is printed in a good quality (in black and white, which short not cause any problems).

Ein-Tim commented 3 years ago

@Timo1993

Okay, thanks. You are explicit mentioning Xiaomi here. Do you have another device to try if the QR-Code can be scanned with another device?

vaubaehn commented 3 years ago

@Timo1993 What @Ein-Tim suggested would be very helpful: scanning with a different Android device, but also using CWA and CovPass.

Did you also try to scan from a bigger distance? >1m I also heard it can help to turn the device 90 degrees (greetings @tangomanni)

Has the certificate been issued in Germany?

What does the certificate cover?

MikeMcC399 commented 3 years ago

@Timo1993

Normally even if you try to scan in any QR code (which is not even a vaccination certificate) you will get at least an error message.

dsarkar commented 3 years ago

@Timo1993 Thank you for reporting. Please, could you send an email to CoronaWarnApp@rki.de, describing your issue, mentioning also this GitHub issue #3514 and also attach your vaccination QR-code. The developers are in contact with RKI. Thank you very much.

Best regards, DS

Corona-Warn-App Open Source Team

tangomanni commented 3 years ago

@Timo1993 Did you try to scan the QR Code with the smartphone rotated by 90 degrees ? This helped definitely in my case.

Timo1993 commented 3 years ago

@Timo1993

Okay, thanks. You are explicit mentioning Xiaomi here. Do you have another device to try if the QR-Code can be scanned with another device?

I tested it on a Samsung Galaxy Tab A7 with the same error. I have two QR codes (double vaccination with biontech). I also tried to rotate the device. I do not get any error (it simply does not recognize the code).

Does the code work directly after a vaccination or do I have to wait two weeks before I can scan it?

MikeMcC399 commented 3 years ago

@Timo1993

Does the code work directly after a vaccination or do I have to wait two weeks before I can scan it?

You should not need to wait before scanning. The app takes care of telling you if you are fully vaccinated or not by checking the vaccination date against the current date.

I would definitely recommend following @dsarkar's advice in https://github.com/corona-warn-app/cwa-app-android/issues/3514#issuecomment-865896330 to send in a copy of your certificate to the developers for independent checking.

Ein-Tim commented 3 years ago

Two Twitter users reporting the same problem: https://twitter.com/wanoppeln/status/1407270853402898433?s=20 & https://twitter.com/ClaudiaKSchmidt/status/1407225172743032834?s=20

Environment of the first user:

Environment of the second user:

No success on any of the devices.

MikeMcC399 commented 3 years ago

Regarding the question of whether you can scan a certificate before 14 days have elapsed - yes you can.

To see the screenshots read the German language blog announcing the 2.3 version. The English language version of the blog is incomplete in this respect.

vaubaehn commented 3 years ago

Looks like, there are many similar reports in Google Play Store reviews at the moment. This one suggests, it's a problem in the layout, when the document is created from the back-end: Screenshot_2021-06-23-10-24-17~2

Timo1993 commented 3 years ago

Looks like, there are many similar reports in Google Play Store reviews at the moment. This one suggests, it's a problem in the layout, when the document is created from the back-end: Screenshot_2021-06-23-10-24-17~2

I will give it a try. The left side of the QR code might cause some problem (there is not enough margin).

vaubaehn commented 3 years ago

Looks like, there are many similar reports in Google Play Store reviews at the moment. This one suggests, it's a problem in the layout, when the document is created from the back-end: Screenshot_2021-06-23-10-24-17~2

I will give it a try. The left side of the QR code might cause some problem (there is not enough margin).

If the trick works also for you, then there are probably thousands of people affected of the same problem, and it should be fixed urgently...

Timo1993 commented 3 years ago

I will report in a few hours if it works. But I already noticed that there are some mm of the code missing on the left side.

vaubaehn commented 3 years ago

@Timo1993 So, seems to be quite likely to be a layout problem.

@thomasaugsten @dsarkar @heinezen Sorry for pinging, but could be good to verify it soon... Is it possible for you to check the layout of the currently generated DCC documents (in pharmacies etc)? If you are able to confirm the issue, I guess it should be fixed asap, because not only there are problems when importing the DCC into the phone. The paper printouts might also be rejected by verifier apps during border control, and people might not know before...

MikeMcC399 commented 3 years ago

@vaubaehn

There are probably multiple software implementations creating the certificates and printing QR codes. Do we know where the problematic QR codes are coming from?

Are there any regional hot-spots like some states affected more than others?

MikeMcC399 commented 3 years ago

@Timo1993

I will report in a few hours if it works. But I already noticed that there are some mm of the code missing on the left side.

Could you say where you got your vaccination certificate from?

Also, would you check to see if your print-out conforms to the recommendations in https://ec.europa.eu/health/sites/default/files/ehealth/docs/covid-certificate_paper_guidelines_en.pdf regarding 1cm margins and QR code size of 50 - 60 mm? Does your certificate look like the example in this document or is it completely different? Did you already send a copy of your certificate to CoronaWarnApp@rki.de?

vaubaehn commented 3 years ago

@MikeMcC399 If I understood it correctly, the DCCs are centrally signed and documents generated from the T-Systems' backend. So it would affect everyone.

Edit: Places like pharmacies etc. are using a also centrally maintained web-fronted (which makes sense for most compliance of certificates and least implementation effort for related parties), and documents for printing can be retrieved in the front-end.

Edit2: Issuing server is IBM/Ubirch, I was wrong in that point. But I'm not sure if that also generates the documents. And you're right, it would be possible to have several different software implementations in parallel using same API endpoints. But as far as I could see, probably most use the same implementation - otherwise the early start of DCC issuing would not have been possible.

tangomanni commented 3 years ago

Hi, my certificate was printed out by a pharmacy in Regensburg. I am not sure if the problem I had (solved by rotating my Smartphone) is due to the same reason as discussed here. Greetings

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Von: @.> Gesendet: Mittwoch, 23. Juni 2021 12:02 An: @.> Cc: @.>; @.> Betreff: Re: [corona-warn-app/cwa-app-android] QR Code not readable on Xiaomi (#3514)

@MikeMcC399https://github.com/MikeMcC399 If I understood it correctly, the DCCs are centrally signed and documents generated from the T-Systems' backend. So it would affect everyone.

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dsarkar commented 3 years ago

Dear all, thanks for contributing and gathering information, which is very helpful indeed!

This issue is considered internally high priority. Although there might be different root causes, currently it seems that the majority (rather all of them) of QR codes are correct, but not printed with sufficient quality. We are in contact with the corresponding entities.

Corona-Warn-App Open Source Team

Timo1993 commented 3 years ago

@vaubaehn

There are probably multiple software implementations creating the certificates and printing QR codes. Do we know where the problematic QR codes are coming from?

  • Pharmacies?
  • Doctors surgeries?
  • Vaccination centers?

Are there any regional hot-spots like some states affected more than others?

I got it from Doctors surgeries.

dsarkar commented 3 years ago

disregard

Ein-Tim commented 3 years ago

PR #3531, merging into release/2.4.x, sets the error correction level to medium (currently it's quartile). This will maybe also improve this situation(?).

EDIT: No it won't, see https://github.com/corona-warn-app/cwa-app-android/issues/3514#issuecomment-866847231.

vaubaehn commented 3 years ago

@dsarkar I thought it could be easy to check myself, so I went to pharmacy to get my vac-DCC (by chance it fitted well to my schedule - I'm not THAT overidentified 😉 ). My QR codes are fine. However, I noticed that the margin from paper border to edge of QR code are 0,9cm only. When several people report that the left border of the QR code is cut a very little (hence cannot be scanned), then it might be a problem between PDF-Reader and printer of the printing location. However, it was not easy to reproduce the problem, but in this combination it works:

While this is a printing issue, it might be mitigated by layouting the QR code a couple of millimeters to the right, reducing the distance between right edge of QR code and text a little. Looks less nice then, but better safe than sorry 😉

@Timo1993 and @tangomanni could you take a look at your print out, and tell, if the fine line above the QR code is exactly as in this picture?

or does the fine line align (start) exactly with the QR code's edge?

harambasicluka commented 3 years ago

PR #3531, merging into release/2.4.x, sets the error correction level to medium (currently it's quartile). This will maybe also improve this situation(?).

No, the change is only about the generated QR Code which is displayed, this is completely decoupled from the scanning.

Ein-Tim commented 3 years ago

@harambasicluka

Thanks, will adapt my comment!

dsarkar commented 3 years ago

@vaubaehn will forward your observations. Thanks.

Timo1993 commented 3 years ago

I can verify that the problem was caused by the margin on the left side. It was 0.5cm and therefore there was not the left border of the QR code. I added a line with a pencil and it worked without any problem. So this might be a general problem. I would recommend to place the QR code not at this position.

Special thanks to @vaubaehn for the hint to draw a line.

tangomanni commented 3 years ago

Hi,

the fine line starts about 3mm away from the page border, the QR-code edge is 4mm away (it’s not aligned but much closer than in your Picture).

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Von: @.> Gesendet: Mittwoch, 23. Juni 2021 15:34 An: @.> Cc: @.>; @.> Betreff: Re: [corona-warn-app/cwa-app-android] QR Code not readable on Xiaomi (#3514)

@dsarkarhttps://github.com/dsarkar I thought it could be easy to check myself, so I went to pharmacy to get my vac-DCC (by chance it fitted well to my schedule - I'm not THAT overidentified 😉 ). My QR codes are fine. However, I noticed that the margin from paper border to edge of QR code are 0,9cm only. When several people report that the left border of the QR code is cut a very little (hence cannot be scanned), then it might be a problem between PDF-Reader and printer of the printing location. However, it was not easy to reproduce the problem, but in this combination it works:

While this is a printing issue, it might be mitigated by layouting the QR code a couple of millimeters to the right, reducing the distance between right edge of QR code and text a little. Looks less nice then, but better safe than sorry 😉

@Timo1993https://github.com/Timo1993 and @tangomannihttps://github.com/tangomanni could you take a look to your print out, and tell, if the fine line above the QR code is exactly as in this picture?

[https://user-images.githubusercontent.com/68376758/123101483-6999b100-d434-11eb-851c-0837de1cb915.png]https://user-images.githubusercontent.com/68376758/123101483-6999b100-d434-11eb-851c-0837de1cb915.png

or does the fine line align (start) exactly with the QR code's edge?

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vaubaehn commented 3 years ago

Hi and thanks @tangomanni ,

the fine line starts about 3mm away from the page border, the QR-code edge is 4mm away (it’s not aligned but much closer than in your Picture).

that would mean, that your QR code is not cut-off at the left side. But it proves, that a cut-off is actually present. Enjoy your day!

Edit: As @tangomanni got his DCC from pharmacy and @Timo1993 got his from doctor, it seems to be more a general problem (that probably may arise independently of implemented software - but if PDFs were generated centrally by a server, a simple fix could prevent future issues. Anyway, there seem to be many problematic paper QR codes out now.)

DerVogel2020 commented 3 years ago

Edit: As @tangomanni got his DCC from pharmacy and @Timo1993 got his from doctor, it seems to be more a general problem (that probably may arise independently of implemented software - but if PDFs were generated centrally by a server, a simple fix could prevent future issues. Anyway, there seem to be many problematic paper QR codes out now.)

I don't think so: I got my certificate from a pharmacy and had no problems with scanning (the left edge of the qr code is 7mm away from the left edge of the paper). As every doctor and every pharmacy uses different kind of printers and printer settings, it can be very difficult to move the qr code far enough away from the border.

vaubaehn commented 3 years ago

@DerVogel2020

I got my certificate from a pharmacy and had no problems with scanning (the left edge of the qr code is 7mm away from the left edge of the paper).

Same here.

I don't think so

Writing "it seems to be more a general problem" I mean, that this problem may occur in different settings, it is not a must obviously.

As every doctor and every pharmacy uses different kind of printers and printer settings, it can be very difficult to move the qr code far enough away from the border.

This is true, but if you do a little, then you will reduce the number of problematic QR codes at least. This is a small mitigation, not a solution that warrents 100% perfect QR codes.

vaubaehn commented 3 years ago

Another idea: text and QR code could be swapped: text on left and QR code on the right. Then it gets very unlikely that parts of the QR code are cut off. As "our" vac-DCCs layout seems to be a "German solution" (compared to the guideline that was linked from @MikeMcC399 before: https://ec.europa.eu/health/sites/default/files/ehealth/docs/covid-certificate_paper_guidelines_en.pdf) it might be done by the related entities without further headache on being complient to the EU guidelines.

Edit: For a nicer look of the text in this case, "Silbentrennung" together with "Blocksatz" might help to enhance the style. But imho, "functioning" should have higher priority than "beauty" here...

MikeMcC399 commented 3 years ago

@vaubaehn I think you are right that the PDF certificates are created by a central service, which is what the Open Source documentation https://github.com/Digitaler-Impfnachweis/certification-apis implies. I had missed that previously because it wasn't part of the examples on that site. I can't find any open source for the PDF certificate generation though. It would be good to have a source code definition of the layout.

I joined the active testers and went to my local pharmacy this afternoon. They first tried to persuade me that I didn't need a digital certificate until I had my second dose, but I insisted and then they did it (which took about 10 minutes). When the lady came back she then told me I shouldn't bother with the Corona-Warn-App (haha, she was talking to the wrong person) and the CovPass App was a lot simpler. I explained what I knew about the differences to her, thanked her and left.

The printed certificate was in black and white.

I had no problems to scan the certificate into CWA and into CovPass App. The CovPassCheck App verified it from both the other two apps, in the sense that it confirmed the vaccination status was incomplete.

Jo-Achim commented 3 years ago

I could imagine that the problem is actually here:

As every doctor and every pharmacy uses different kind of printers and printer settings, it can be very difficult to move the qr code far enough away from the border.

Here as an example a working laser print from the DCC from a Bavarian pharmacy: QR-DCC (10 mm from left margin.)

Best regards.

MikeMcC399 commented 3 years ago

@vaubaehn I put your suggestion about modifying the format into a separate issue https://github.com/corona-warn-app/cwa-documentation/issues/644. I have to apologize to you though because when I wrote the suggestion I had missed the fact that you already made the suggestion! I gave you credit for it anyway.

vaubaehn commented 3 years ago

@MikeMcC399

I put your suggestion about modifying the format into a separate issue corona-warn-app/cwa-documentation#644.

Great! It's there where it belongs to, and it's fast! Edit: and it's good to know, "CovPass is reading here"... 😉

I have to apologize to you though because when I wrote the suggestion I had missed the fact that you already made the suggestion!

No worries! ☘️

And I enjoyed to read your report from https://github.com/corona-warn-app/cwa-app-android/issues/3514#issuecomment-866977483 .

Have a nice night!

rakso10000 commented 3 years ago

I had the same issue but it was a digital version so it definitely was not a printing issue. Turns out the colors of the QR code were inverted. What would be the right place to contact about this? Should I just tell the doctor?

dsarkar commented 3 years ago

@rakso10000 Thanks for your report. So you were sent an email with a PDF document, and you received a kind of B/W "negative" of the QR code?

Corona-Warn-App Open Source Team

dsarkar commented 3 years ago

If you think that the QR code was generated wrong: In principle you could also contact one of these: https://digitaler-impfnachweis-app.apps.public.bfarm.de/kontakt/

rakso10000 commented 3 years ago

@rakso10000 Thanks for your report. So you were sent an email with a PDF document, and you received a kind of B/W "negative" of the QR code?

Corona-Warn-App Open Source Team

Yes, exactly.

If you think that the QR code was generated wrong: In principle you could also contact one of these: https://digitaler-impfnachweis-app.apps.public.bfarm.de/kontakt/

I will do that then, thanks!

dsarkar commented 3 years ago

@rakso10000 I think the community here would be very interested about your feedback here once your issue was attended and resolved. Thanks.

vaubaehn commented 3 years ago

@rakso10000

@rakso10000 Thanks for your report. So you were sent an email with a PDF document, and you received a kind of B/W "negative" of the QR code? Corona-Warn-App Open Source Team

Yes, exactly.

Is your "system" running on dark-mode? Or are special settings for "Erleichterte Bedienung" are active? I remember from earlier windows versions that it was possible to invert colors, which may result in a kind of "dark mode experience" that would have the effect that you described for your QR code.

@rakso10000 I think the community here would be very interested about your feedback here once your issue was attended and resolved. Thanks.

Yes, very much!

vaubaehn commented 3 years ago

@rakso10000

I had the same issue but it was a digital version so it definitely was not a printing issue.

then it's a different issue, as this issue figured it out that there is a printing issue. Anyway, a follow up about your issue would be nice. Thanks in advance!

rakso10000 commented 3 years ago

Is your "system" running on dark-mode? Or are special settings for "Erleichterte Bedienung" are active? I remember from earlier windows versions that it was possible to invert colors, which may result in a kind of "dark mode experience" that would have the effect that you described for your QR code.

It is, but the code is displayed the same way on my phone and other devices. I also just changed Windows to light mode and it was still displayed that way.

then it's a different issue, as this issue figured it out that there is a printing issue. Anyway, a follow up about your issue would be nice. Thanks in advance!

You're right, I should have posted this in a separate issue. Sorry! I will definitely update you when I get a reply.

MikeMcC399 commented 3 years ago

@rakso10000 I have added an FAQ request for this scenario https://github.com/corona-warn-app/cwa-website/issues/1422.

If you think it would be worthwhile to discuss this in more detail, then please go ahead and open a new issue in https://github.com/corona-warn-app/cwa-documentation (since the problem will be independent of Android or iOS).

Thanks to @vaubaehn for recognizing the cause!

rakso10000 commented 3 years ago

@rakso10000 I have added an FAQ request for this scenario corona-warn-app/cwa-website#1422.

If you think it would be worthwhile to discuss this in more detail, then please go ahead and open a new issue in https://github.com/corona-warn-app/cwa-documentation (since the problem will be independent of Android or iOS).

Thanks to @vaubaehn for recognizing the cause!

Thank you, however only the QR code was inverted, the rest of the file was not. (This is the last reply to this issue on the wrong thread, sorry.)