Images are not attached to the signature in the onMessageSend event in Outlook Online and the new Outlook

[barisbikmaz]

Provide required information needed to triage your issue

We are listening to the "OnMessageSend" event in our Outlook addin. While the message is send, we are inserting the signature for the user. We realized that in Office Online (and in the new Outlook) inline images are missing in the received signature.

• When inserting the signature with another event like on "OnMessageNew" in Office Online the inline image is shown successfully.
• When using the classic Outlook App on Windows the signature insertion with inline images is also working sucessfully with the "OnMessageSend" event.

Your Environment

• Platform: Office on the web / new Outlook
• Host: Outlook
• Operating System: Windows 11
• Browser: Chrome

Expected behavior

Inline images in signatures shoud be shown to the mail recipient.

Current behavior

When inserting the Signature "OnMessageNew" the signature looks like this

When inserting the signature again with the "OnMessageSend" event the received signature looks like this

Link to live example(s)

Run following code when the "OnMessageSend" event is triggered.

function testOnSend() {
    const signature = `<p>Greetings John Doe</p>
<img src="cid:homer.jpg" width="100" />`;

    if (!Office.context.mailbox.item) {
        return;
    }

    const item = Office.context.mailbox.item;

    return new Promise(resolve => {
        item.addFileAttachmentFromBase64Async(
            imageBase64,
            'homer.jpg',
            { isInline: true },
            () => {
                item.body.setSignatureAsync(
                    signature,
                    {
                        coercionType: Office.CoercionType.Html,
                    },
                    () => resolve(true),
                );
            },
        );
    });
}

await testOnSend();

[neprasad-microsoft]

Hi @barisbikmaz Can you confirm if this works on New Outlook on Windows? Also please collect the logs and share it with us. https://github.com/OfficeDev/office-js/wiki/Collecting-log-files-for-Outlook-Add%E2%80%90ins-issues If possible, share your add-in manifest with us. This will help in faster debugging. You can share the files in a private repo and give access to exextoc.

[barisbikmaz]

@neprasad-microsoft Added all the log files for Office Online to https://github.com/barisbikmaz/onsend-issue/

I can currenly not check on the new outlook because my side loaded addin is not running on it. Currently don't know the reason why because it is running on classic Outlook and on the web.

[barisbikmaz]

@neprasad-microsoft Today apps in the new Outlook are working again and I could test the signature. The same problem as in Outlook Online happens also with the new Outlook. Inline images which are added in the OnSend event are not shown in the signature.

[anjalitp]

Thanks for reporting this issue regarding Signature API. It has been added to our backlog. We unfortunately have no timelines to share at this point.

Internal tracking ID: 4779537