Can't load Google Docs/Sheets homescreens

[Hoopyy]

Google Docs/Sheets pages don't load the recently used files, it just shows the multicoloured folding circle loading icon. Tried disabling all addons, disabling tracking protection, but doesn't help. Creating a new user profile does work however, so I assume this has to do with my user.js settings. Any help on finding which one? Not sure if I can upload my user.js back into ffprofile.com and troubleshoot by disabling/enabling options, don't have the original .zip file of my profile any more.

[allo-]

Try pressing F12 and look at the console tab for errors and at the network tab for blocked connections. Otherwise the only option is to disable options one by one to see which one is causing the problem.

[Hoopyy]

Getting a lot of "Cross-Origin Request Blocked: The Same Origin Policy disallows reading the remote resource at https://play.google.com/log?format=json&hasfast=true&authuser=0. (Reason: CORS request did not succeed). Status code: (null)." Some with data:text/plain;base64,Cg== instead of the play.google.com link

[allo-]

Did you install any adblock, privacy badger, uMatrix addon with the profile? Especially with uMatrix you have to allow thirdparty requests on each site.

[Hoopyy]

I installed ublock, privacy badger, decentraleyes and clearurls. But surely disabling them would solve the issue if they were causing one?

[allo-]

Yes. Maybe you have configured some other stricter network rules?

Any maybe the error isn't really related. Also have a look at referer, cookies, and so on. Especially on authentication (why does the api deny the CORS request?) Referer can break a few things.

Go through the settings in the prefs.js file (or if you still have the page open, the preview on the finish page) and try to see which ones may be related. Most can be toggled in about:config without restarting the browser or creating a new profile.

[Hoopyy]

Found the solution, setting network.http.referer.spoofSource to false. Thanks for your help!