Plesk / malleable SMPT Problem

[MaikelO]

hello, I'm desperate ... We rent a virtual server with Plesk.

In the past we have been on a spam list, but now all the lists on our ipaddres are clean.

We have now been a month further and our SMTP mail server still does not work.

Does anyone have a tip?

Service > SMTP> LastError
The socket connection to the remote host failed. The host was either not contactable or it rejected your connection.
(http://kb.odin.com/en/121457)

[MailEnable-Ian]

Hi,

Most likely the rejections are occurring because your reverse DNS record (PTR) for ourbrand.nl is incorrect. Please nslookup results below:

Non-authoritative answer:
Name: ourbrand.nl
Address: 81.169.137.219

> set type=mx
> ourbrand.nl
Server: hyper.mailenable.com.au
Address: 192.168.2.109

Non-authoritative answer:
ourbrand.nl MX preference = 20, mail exchanger = fallback.axc.nl
ourbrand.nl MX preference = 10, mail exchanger = mail.ourbrand.nl

fallback.axc.nl internet address = 159.253.5.241
mail.ourbrand.nl internet address = 81.169.137.219
> set type=ptr
> 81.169.137.219
Server: hyper.mailenable.com.au
Address: 192.168.2.109

Non-authoritative answer:
219.137.169.81.in-addr.arpa name = h2415783.stratoserver.net

As you can see above the PTR record is resolving to h2415783.stratoserver.net and not mail.ourbrand.nl and would explain why Gmail is rejecting your inbound messages.