We have a JavaScript Outlook on-send add-in (not Smart Alerts) that has recently been updated and published. The add-in is hosted on an Azure Storage Blob.
When Exchange admins go to remove the add-in, then re-add it using Integrated Apps, and follow the instructions at https://learn.microsoft.com/en-us/microsoft-365/admin/manage/manage-deployment-of-add-ins?view=o365-worldwide, there is an error that says that the manifest file has failed:
Integrated Apps Failed Validation Message
How can we correct this problem?
Our manifest file is located at https://addins.sperrysoftware365.com/prd-addins/SafeguardSend/manifest.xml?ver=3.2
Why does it work when sideloading it into Outlook but not work when admins deploy it through Integrated Apps?
I suppose they do the same check as the store does. Try to run the following command to validate the manifest file on your machine:
npx office-addin-manifest validate -p MANIFEST_FILE
The office-addin-manifest package/tool calls a service endpoint (which is also used by the store) and just report the results.