Migration from Exchange on prem to Exchange online

Will migration from on-premise Exchange to Exchange Online stop working as of October 2026?
You can see this error in the logs:"Error: The job encountered too many transient failures (61) and is quitting. The most common failure is CommunicationErrorTransientException with the hit count 60." And in IIS you see error 401

 
The solution is to recreate the migration endpoint using the UPN (email address removed for privacy reasons) instead of "Domain\user". Simply modifying the existing endpoint will not work.