The following is the report that was sent to me:

This is the mail system at host  relay.mailchannels.net .

I'm sorry to have to inform you that your message could not
be delivered to one or more recipients. It's attached below.

For further assistance, please send mail to postmaster.

If you do so, please include this problem report. You can
delete your own text from the attached returned message.

                   The mail system

< admission@srmuniversityinfo.zohodesk.com >: host
     zm-apps2.zoho.com [216.52.73. 56] said: 452
    < admission@srmuniversityinfo.zohodesk.com > Mailbox delivery restricted by
    policy error (in reply to RCPT TO command)

Final-Recipient: rfc822;  admission@srmuniversityinfo.zohodesk.com
Original-Recipient:  rfc822;admission@srmuniversityinfo.zohodesk.com
Action: failed
Status: 4.0.0
Remote-MTA: dns;  zm-apps2.zoho.com
Diagnostic-Code: smtp; 452 < admission@srmuniversityinfo.zohodesk.com > Mailbox
    delivery restricted by policy error