When I first tried migrating iCloud Mail to Office 365, I ran into a few unexpected errors like login failures and emails not syncing properly. After some trial and error, I realized most issues were caused by incorrect credentials or missing permissions, so double-checking account settings really helped. Sometimes, the connection would break due to network instability, so restarting the process fixed it. Later, I found that using a tool like the SysInfo iCloud Backup Tool reduced these errors because it handled the connection and migration process more smoothly without requiring too many manual steps.
Read more: https://www.sysinfotools.com/icloud-backup.php