Azure SQL DB mirroring issue

Thank you for sharing the details. It seems like you're encountering issues with maintaining the replication between your Azure SQL database and Fabric after the initial successful sync.

Based on the errors you've listed, here are a few suggestions to consider:

1. Source Connection Unknown: Double-check that the source database still exists and that the connection string or linked service hasn't changed or expired.
2. Permissions: Ensure that the identity used for the connection (especially if using a managed identity) has the necessary permissions on both the source and target environments.
3. Managed Identity Retrieval Failure: This could be related to a temporary issue with Azure AD or a misconfiguration in the Fabric environment. Try re-authenticating or reassigning the managed identity.
4. Activity ID Undefined: This might indicate a deeper issue in the Fabric service or a bug. Reviewing the diagnostic logs or raising a support ticket with Microsoft might help.

Since your SAMI is enabled, it might be worth verifying that it is correctly assigned and has the right roles (e.g., SQL Server Contributor, Reader, etc.).

If anyone has encountered a similar issue and found a resolution, your insights would be greatly appreciated.