I'm having problem with one of my target email recipient, when I tried to send email to abacus@abacusevents.com, I got this error message from my email server:
Diagnostic information for administrators:
Generating server: mail.domain.com
abacus@abacusevents.com
mail.abacusevents.com #<mail.abacusevents.com #5.0.0 smtp; 554 "Refused. You have no reverse DNS entry. Contact abuse@suresupport.com for details."> #SMTP#
which PTR records should I add into my intenral DNS or my ISP DNS server ?