MS Exchange mailbox quarantined Error

Problem : 

Delivery has failed to these recipients or groups:
User name (username@xyz.com)
Your message wasn't delivered because the recipient's mailbox is quarantined. If the problem continues, please contact your helpdesk.
The following organization rejected your message: mail.domain.com

Diagnostic information for administrators:
Generating server: mail.domain.com
Total retry attempts: 1
username@xyz.commail.domain.com
Remote Server returned '550 5.7.9 STOREDRV.Deliver; Recipient mailbox quarantined.; STOREDRV.Deliver.Exception:StorageTransientException.MapiExceptionMailboxQuarantined; Failed to process message due to a permanent exception with message Cannot open mailbox


Solution : 

this is caused by either user reaching maximum quota limit or it is could be due to exchange server running out of disk space.

In my case it was due to disk space on the server, I had to truncate mail databases logs and other logs created by exchange and also I had to change the quota limit for the user even though it was not reached yet , also rebooting the server will be required.