In exchange, if you have moderation on your distribution list and try and moderate a message sent to it, you might receive the following error message:
“Your message can’t be moderated because the approval system is too busy and can’t accept messages now. Please try resending your message later, or contact the recipient directly.”
The reason that you are receiving the above error message is because the Arbitration Mailboxes are not available. They could have been removed as part of migration where someone just shutdown an Exchange Server and then deleted it or the system mailboxes are corrupt or they simply don’t exist in AD or they are on a store that is dismounted.
If the above is true then you can re-create them by running the setup command in Exchange with the PrepareAD switch and it will re-create them.
To check if your arbitration mailboxes exist, you can run the following command:
- Get-Mailbox -Arbitration
If they are on a server that is offline, then bring the server back online and move the mailboxes before removing that exchange server, you will get an error message that the server has mailboxes when you try remove it.
To move the arbitration mailboxes, you can run the command above with a extra | as follows:
- Get-Mailbox -Arbitration | New-moveRequest -TargetDatabase DAG01-Store1
Once completed, don’t forget to remove the move requests that you performed.
Hope it helps.