Email Not Working For 3 Days - Server Side Issue

Email Not Working For 3 Days - Server Side Issue

Just wondering if there is a wide spread issue regarding zoho.com email, or whether it is just my account?

Have been unable to send or receive email for 3 days now, and anyone that tries to send me an email gets the following message:

"This message was created automatically by mail delivery software. 


A message that you sent could not be delivered to one or more of its recipients. This is a permanent error. The following address(es) failed: 


  username@zoho.com


    host smtpin.zoho.com [204.141.42.120]


    SMTP error from remote mail server after RCPT TO:<username@zoho.com>:


    552 5.1.1 <username@zoho.com> Mailbox delivery failure policy error


I have sent numerous email messages and raised a support enquiry, but have heard nothing back, making me think there is maybe a wider issue preventing support from replying?

Any help appreciated.