Delivery has failed to these recipients or groups

[Erland Medrano]

Hi Team,

Kindly help us on this issue. We've encountered a problem on delivering an email to a certain email address.

Once the email is sent to this address a bounce back email returned to the sender. 

I attached here the error for your reference.

Thanks!

[Hrvoje (Harry) Dogan]

Hi Erland,

As the error says, the receiving server is rejecting your connection because your ESA does not have a reverse DNS entry. Talk to your DNS admins to add a PTR record for 216.12.221.35 to point at your hostname.

[John]

I have the same issue. I would like to know if I will add a a PTR record for 216.12.221.35 in the ISP?

[Mathew Huynh]

Hey John,

If the error seen on the NDR Is referencing the same, then yes you need to ensure that your mail server's public IP (that connects to other MTAs) has a complete forward and reverse DNS available for lookups as some servers do DNS checks to may reject if a DNS check fails or is unavailable.

Regards,
Matthew