ExchangeOnline MailboxBackupException #47 Job exception

Discovered Version：v9.0

Question

Backing up Exchange Online, job failed with #47 job exception. 
vinchin system log: m365_backup_server log show: [WARN:600037#user can not backup]: user: xxx.com can not backup.. m365_backup_server_task/m365

Answer

Issue Description

A specific user mailbox type is not within supported scope, causing backup task failure.

unsupported email scope:

• Removed from the deleted items folder: non-mail items
• contact groups
• notes
• deleted items within retention (including litigation hold)
• archive mailbox data
• shared calendar invite emails.

Resolution

Exclude Unsupported User Mailbox

• Edit the backup task and exclude unsupported mailbox users from backup task.
• run the backup task again.