I had this issue yesterday and got resolved, but the same problem I got today also.
I am using the ZOHO mail for my business purpose and don't send any mail in bulk nor I use any abusive words in the mail and I as far as I know I don't even send mail to wrong mail Id;s even though getting this error again.
I would like to know the reason for this error so please reply back ASAP
This Mails Id: chintan.p@shaligraminfotech.com
Regards
Chintan