Mail only sending not receiving on Exchange

My MacBook has developed an issue with mail where it sends but not receives mail.

To get new mail I have quit and start mail in safe mode, holding down Shift.

No connection issues are reported and mail claims it’s synced even when it’s not.

Can anyone advise how I fix this?

Rebuild the local database?

Perhaps rebuilding the database will fix it. Can’t hurt. My first step would be to delete the account, then re-add the account to Mail. Also, if an Exchange server run by your employer, find out from IT if there might be some sort of issue.