Office 365 backup fails for some mailboxes
I have random office 365 mailboxes fail backup with error. Windows error: (0x80070057) The parameter is incorrect.
A single system is backing up all office 365 mailboxes. some work correctly others don't. I have deleted the backups and the backup files and it still occurs.
Multiple customers have the same problem so it can't be the site or the office 365 domain.