Did you by any chance get answer to this question, because i encountered the same issue.
Graph/Teams - Rich notification are not supported for this resource in 'app + user' context
I'm trying to set up rich notifications for a channel subscription like in the docs below.
New or changed messages in a specific Teams channel: /teams/{id}/channels/{id}/messages
I'm supplying the details to the subscription url like below with ROPC auth flow.
{
"changeType": "created,updated",
"notificationUrl": "https://f554-118-110-222-226.ngrok.io/api/teams/events",
"resource": "teams/TEAM_ID/channels/CHANNEL_ID/messages",
"expirationDateTime": "2021-10-20T02:55:53Z",
"encryptionCertificate": "encryptionCertificate",
"encryptionCertificateId": "encryptionCertificateId",
"includeResourceData": true,
}
I should have all permissions necessary to access this resource since I can create a subscription when includeResourceData is false. However, I'm getting the following error when includeResourceData is true and I supply an encryption cert.
Operation: Create; Exception: [Status Code: BadRequest; Reason: Rich notification are not supported for this resource in 'app + user' context. Please set includeResourceData field to false.]
I think it might be with how my auth and permissions are set up but I'm not entirely sure what this means. Any help is appreciated