The Exchange Server is too Busy to Process the Request

• This article is for Windows only

When taking a mailbox-level backup, the backup may fail with the following error:

• Backup of following mailboxes failed: The following mailboxes could not be backed up. The Exchange server is too busy to process the request.

A list of mailboxes will be shown.

This error occurs when the Exchange server is too busy to provide information to Carbonite Safe Server Backup. This happens most often for Exchange Online, and is caused when Exchange reaches certain preconfigured limits.

When these limits are hit, the Exchange server rejects CSSB's requests for data. CSSB will retry, but backup of a mailbox will fail if the requests continue to be rejected.

This problem can usually be resolved by increasing the HangingConnectionLimit value in the Exchange web.config file. Please read the "ErrorServerBusy" section in this Microsoft Knowledge Base article.

Modifying Exchange configuration settings such as the web.config file is outside of the scope of Carbonite Support. Please contact your system administrator.