We just started using Exchange Online and it has been working great. Our current plan is to use Exchange Online, but when someone quits our company we will migrate the mailbox back on-premises for a few months, to free up licenses, and then delete the mailbox 4 months later once we confirm that their boss, etc has not requested access to their email, etc.
Normally, I can migrate mailboxes back on-premises with no issues, but now I have 1 that is stuck ay syncing for days. Does not matter if I use Exchange Admin Center, powershell, etc the mailbox never migrates 100%. This is not normally an issue, but have increased the error count for this mailbox, etc and it just stalls. Anyone have any ideas or know of some good logs I can look through, etc.?