The forward lookup (A) of the hostname hostname did not match the reverse lookup (PTR) for the IP Address.
Example of a correctly matching pair of records:
(A) lookup for smtp.mxtoolbox.com resolves to 22.214.171.124
(PTR) lookup for 126.96.36.199 reverses to smtp.mxtoolbox.com
Some receiving mail servers may use this as an indication of a possible spam source in a scoring system. Most will not reject incoming mail solely on this basis. We recommend that you contact your ISP and ask them to setup a reverse record (PTR) that matches the hostname of your mail server.
Are you confident your email is getting through?
You rely on email for business critical communication, so you need to know your email has been delivered to your customers and you need to know who is sending email on your behalf.
MxToolbox is YOUR expert on email deliverability. Delivery Center analyzes your DMARC, DKIM and SPF to give you the insight you need to make email configuration changes and get your emails to your customer's inboxes.