Outlook add-in event based activations not working on web browser

Question

I'm working on an outlook add-in I can't get event-based activations to work on the web client (but do actually work on the Mac Outlook app). I've been trying to run the examples hosted on github, both outlook-set-signature and outlook-encrypt-attachments provided by the Microsoft team. And add-in is correctly loaded. I can manage to open the sidepanel and follow the instructions, but nothing changes. Trying the same thing using the Outlook client on Mac OS works as expected.

Here are my reproduction steps:

• Visit https://outlook.live.com/calendar/
• New event > Get Add-ins > My Add-ins > "Add Custom Addins" > From URL > Paste "https://officedev.github.io/Office-Add-in-samples/Samples/outlook-encrypt-attachments/manifest.xml"
• Go back to the calendar app > Click on the three dots button > click "Event Activation Example" addin > The sidepanel shows as expected
• Discard the event and create a new one
• Add a new participant to the event and expect a notification / or add any lightweight attachment and expect an automatically generated encrypted version of the attachment
• Nothing happens 🤷 . According to the docs, a notification message should be shown

This "unresponsiveness" also happens with my own add-in and also in another example provided by the outlook team https://github.com/OfficeDev/Office-Add-in-samples/tree/main/Samples/outlook-set-signature.

BUT, these add-ins do actually work when I use them on my Mac OS Outlook app (OS Version: Ventura). So I'm wondering if there's any limitation for event-based activations for non-365 users using outlook on a web browser.

Answer 1

Event based add-ins are currently supported for commercial accounts as they are only available as part of admin deployment. Supporting event-based activation for user acquired add-ins is on the road map and we will consider this as part of that requirement. We don't have an ETA for this yet.

Answer 2

I'm wondering if there's any limitation for event-based activations for non-365 users using outlook on a web browser

Classic Outlook UI when connected to Exchange on-premises doesn't support the requirement set 1.10 where the event-based activation was introduced.

Modern Outlook UI when connected to Exchange Online: Microsoft 365 subscription, Outlook.com supports the Outlook add-in API requirement set 1.10.

You can find the Outlook client support for specific requirement sets in MSDN.

Also you may find the Debug your event-based Outlook add-in page helpful.