Acronis Backup Cloud: Office 365 mailbox backup completes with warning "An internal server error occurred. The operation failed. The value is set to empty Parameter name: itemId'

Symptoms

You are backing up Office 365 mailboxes with cloud agent.

Backup completes with warning:

Cannot back up Office 365 mailbox item: An internal server error occurred. The operation failed. The value is set to empty Parameter name: itemId

Solution

It is safe to ignore this warning, the mailbox specified in the error message is backed up.

The warning will be removed in the next version of Acronis Cyber Cloud.