550-Verification failed for 550 Sender

[jimr1]

maybe read this thread

PTR record not found

SYSTEM INFORMATION OS type and version REQUIRED Webmin version REQUIRED Please could someone help with this: I have an existing DNS server, Bind enabled, etc. I setup PTR records for a subnet of IPs(for ex: a.b.c.d/24) on it sometime back, and everything is currently working fine. It has just 1-master zone(domainA.com). DomainA is properly setup from the registrar. Dig command locally gives correct results If I do a PTR lookup from mxtoolbox.com, or any lookup portal, I see the …

@Joe

Most of the time your PTR record is out of your control. Your host owns the network block, not you. Some will delegate it on request, others will set it to a value of your choosing…almost never is it something that will Just Work if you set it up in your DNS server without explicit/informed cooperation from your hosting provider.

so from this just set up a ptr record at your hosting provider, if the allow that, or get them to setup a ptr record for you