Emails are bounced via autocract

[MCG COLLEGE OF HEALTH SCIENCE]

My Domain is new & Autocrat is perfectly merged the doc & worked, but I get emails bounced back. I don't see any precise errors, but only emails are bounced.

 

Document successfully created; Document successfully merged; PDF created; Emails Sent:

 

Message blocked
Your message to ...@....com has been blocked. See technical details below for more information.
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The response was:
Message rejected. For more information, go to https://support.google.com/mail/answer/69585