Enquiry Regarding Group Chat Migration Messages Not Reflected in OOTB

Hi Team,

I am reaching out regarding an issue encountered while using the Microsoft Graph beta API for Group Chat Migration.

We followed the documented migration flow using the following endpoints:

1. https://graph.microsoft.com/beta/chats/{chatId}/startMigration
2. https://graph.microsoft.com/v1.0/chats/{chatId}/messages
3. https://graph.microsoft.com/beta/chats/{chatId}/completeMigration

Documentation Link : https://learn.microsoft.com/en-us/microsoftteams/platform/graph-api/import-messages/import-external-messages-to-teams#create-a-team-and-standard-channel-in-migration-mode

The messages were successfully posted to the target chat, and the API returned a 201 Created status code. However, these messages are not reflected in the Out-of-the-Box (OOTB) after migration completion.

Details:

API version: Beta

Authentication: Application Token

Status codes: 201 Created for message posting

Issue: Messages not visible in Teams OOTB after migration

Could you please clarify:

1. Why the migrated messages are not appearing in the Teams client despite successful API responses?
2. Are there additional steps or configurations required to ensure migrated messages are visible in OOTB?
3. Is this a limitation of the beta API, or is there guidance on how to validate migrated messages in Teams?