SMTP error from remote server for TEXT command, host: mx2.zoho.com (74.201.154.201) reason: 554 5.2.3 MailPolicy violation Error delivering to mailboxes

SMTP error from remote server for TEXT command, host: mx2.zoho.com (74.201.154.201) reason: 554 5.2.3 MailPolicy violation Error delivering to mailboxes

Dear Team,

i already send you a mail to  support (at) zoho..... to report the problem.
But maybe other people can use this problem report in future.

we can't receive any incoming mails. 

Problem:  c*****@bummelbu.de :

SMTP error from remote server for TEXT command, host: mx2.zoho.com (74.201.154.201) reason: 554 5.2.3 MailPolicy violation Error delivering to mailboxes


thanks in advance