Send a message to an existing group chat via Mircrosoft Graph

Question

I have a test Teams tenant and have been exploring Microsoft Graph. I want to develop a .net app that can post messages into a group chat. When I try this in the test tenant, using the example from https://learn.microsoft.com/en-us/graph/api/chat-post-messages?view=graph-rest-1.0&tabs=http&source=docs, I get back a 401 with this as the message in the response: "Message POST is allowed in application-only context only for import purposes. Refer to https://docs.microsoft.com/microsoftteams/platform/graph-api/import-messages/import-external-messages-to-teams for more details."

I cannot figure out what this means and I see nothing in the online help that explains it. The link does not help. How do I send a message to a group chat?

Answer 1

Hi @Mike Landi

According to the Graph Api, Application permissions are only supported for migration. This error is therefore reported if you send a message while chatting with application permissions.

When sending a message in a chat, you need to use the delegation permissions ChannelMessage.Send or Group.ReadWrite.All, which will send the message in the chat on behalf of the logged in user, and you need to get a token through auth code flow when using the delegation permissions. You can refer to this document.

Hope this helps.

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