I'm using the /beta endpoints for Microsoft Graph API, but I'm getting an Unauthorized error when trying to create chat messages on behalf of other users (or any user).
In v1.0 of the API, the Create chatMessage method is not Supported, but in Beta it is: https://docs.microsoft.com/en-us/graph/api/channel-post-message?view=graph-rest-beta&tabs=http, as "Teamwork.Migrate.All" permission, which my Application has in Azure.
It is strange, because the same App can create Teams, channels and add members, but not add channel messages.
Anyone know where to look next?
Edit: I got this back now: "You need to add user delegated permissions in your application to at least Group.ReadWrite.All in portal.azure.com and then consent as user or Grant admin consent in portal. And re-run On behalf of a User | Get User Access Token request to update access token."
However, it does not make sense in regards to what the Beta documentation says about the permission "Teamwork.Migrate.All", which my app has as an "Application Permission": "Allows the app to create chat and channel messages, without a signed in user. The app specifies which user appears as the sender, and can backdate the message to appear as if it was sent long ago. The messages can be sent to any chat or channel in the organization."
If I'm an app and I have that permission, what should I do with a User Access Token? I'm using the App Access Token.


