Some addIns are not opening the task pane

[kstuhs]

Provide required information needed to triage your issue

Your Environment

• Platform [PC desktop, Mac, iOS, Office on the web]: Office on the web
• Host [Excel, Word, PowerPoint, etc.]: Outlook
• Office version number: ______
• Operating System: Mac
• Browser (if using Office on the web): Chrome v131.0.6778.204

Expected behavior

Clicking the addin should open the task pane

Current behavior

I haven't been able to identify what is exactly causing it, but when I click certain addins from the addin menu in the message context, the menu closes and the addin doesn't open the task pane. This is true for Send to OneNote along with my own team's addin - Viva Insights seems to open fine. Here's a quick clip to show for Send to OneNote (not sure if it's relevant, but if you look closely you can see that I sometimes have to click several times to open the addin menu):

addin2.mov

Then when I try to open our own addin from the ribbon, it opens a search bar that my team did not create.

The same account with the same addin could work in one Chrome instance and fail in another.

Steps to reproduce

Unfortunately I don't know exactly what the cause is, so I can't reproduce faithfully. One person on my team was able to reproduce with Chrome Canary, then when they updated it went away.

Link to live example(s)

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Provide additional details

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Context

Useful logs

• Console errors
  • There was nothing meaningful in the console when the addin fails to open
• Screenshots (above)
• Test file (if only happens on a particular file)

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[github-actions]

Here are some similar issues that might help you. Please check if they can solve your problem.

• Add-in task pane not opening in Outlook on the web #4075
• Every addin with a sidebar is not loading at all on OWA #3399
• TaskPane not working in New Outlook #5288

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Possible solution (Extracted from existing issue, might be incorrect; please verify carefully)

Solution 1:

We fixed it by doing a minor change to the manifest file. We changed "CustomTab" --> "OfficeTab"

Reference:

• Add-in task pane not opening in Outlook on the web #4075 (comment)

Solution 2:

Opening a mail and then going to compose worked for me! I noticed it was only an inbox mail. I tried one from deleted/archived and that didn't work at first.

Reference:

• Every addin with a sidebar is not loading at all on OWA #3399 (comment)

Solution 3:

We have fixed this issue and it is being rolled out. It should be available latest by tomorrow. In case you still face this issue, then please clear your cache and do a hard refresh and try again.

Reference:

• Every addin with a sidebar is not loading at all on OWA #3399 (comment)

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[manaunl]

We are experiencing the exact same issue. Additionally, we have noticed that the event-based activation for OnMessageCompose, OnMessageRecipientsChanged, and OnMessageAttachmentsChanged does not trigger for our add-in.

This issue is blocking our add-in functionality, as event-based activation is a crucial component. Please provide guidance on resolving this or let us know if a fix is in progress.

[MatthewLowden]

Hi @exextoc ,
This appears to be caused by a failed change that started rolling out yesterday.
Please could you stop the roll-out and revert this?

[MehakFatima24]

Hi @exextoc this is impacting the users in our user base as well, kindly revert this asap so the users are able to use the add-in.

[rickgoud]

Wow...just wow... @exextoc and Microsoft team. How can it be that these type of fundamental issues are not discovered in QA? Can you please set up a program that will prevent these fundamental issues. Add-ins not loading and Events not working are the core of your M365 add-in strategy.

Please, please give this high prio and show to the community you take quality seriously!

[pihlapuro-fi]

Experienced the same behaviour yesterday 19th of March in OWA with our add-in as well.

[arpitsangwanmsft]

Hey @kstuhs / @manaunl / @pihlapuro-fi / @MehakFatima24 !
Can you please share logs as per these instructions so that we can check our telemetry for those specific users as well.