Can you guys check into this? All the notification emails to comcast users are bouncing with the following error…
Connected to 206.18.177.26 but sender was rejected.
Remote host said: 521-EHLO/HELO from sender 204.14.106.10 does not map to mail2.m****here.biz in DNS 521-sending machine name must be provided as a fully 521-qualified domain via EHLO/HELO command.
521-see section 4.1.1.1 and 4.1.4 of RFC 2821
521 521: Comcast requires that all mail servers must have a PTR record with a valid Reverse DNS entry. Currently your mailserver does not fill that requirement. For more information, refer to: Discovery Hub - News & Technology
Looks like something is going on with the reverse DNS lookup.
Many thanks!
Mike