550 Sender IP Reverse Lookup Rejected

#1

I am getting this error when trying to email one of my clients. Does anyone know how this can be corrected? This same client is one of the reasons we switched to MXRoute. What is weird is I was able to email them a few days ago and now I am getting an error. Before switching to MXRoute, when I could not email this client it was because our mail server was on a blacklist, now this… Our their rules just overly strict?

Here is the full error (I changed my domain to xyz and the recipients to xyyz, because I am not sure I should post that on a forum):

Return-Path: lucas@xyz .net
Received: from filter001. mxrelay. co (unknown [94.130.183.33])
by qrelay182.mxroute .com (Postfix) with ESMTP id 04E99160507;
Tue, 18 Jun 2019 10:25:40 -0400 (EDT)
Received: from friday.mxlogin. com (static.104.65.69.159.clients.your-server. de [159.69.65.104])
by filter001.mxrelay. co (Postfix) with ESMTPS id 69F54100991;
Tue, 18 Jun 2019 14:25:38 +0000 (UTC)

Reporting-MTA: dns; qrelay182.mxroute. com
X-Postfix-Queue-ID: 04E99160507
X-Postfix-Sender: rfc822; lucas@ xyz. net
Arrival-Date: Tue, 18 Jun 2019 10:25:40 -0400 (EDT)

Final-Recipient: rfc822; schinger@ xyyz. org
Original-Recipient: rfc822;schinger@ xyyz. org
Action: failed
Status: 5.0.0
Remote-MTA: dns; ttc.xyyz. org
Diagnostic-Code: smtp; 550 Sender IP reverse lookup rejected

Final-Recipient: rfc822; Jartin@xyyz. org
Original-Recipient: rfc822;Jartin@xyyz. org
Action: failed
Status: 5.0.0
Remote-MTA: dns; ttc.xyyz. org
Diagnostic-Code: smtp; 550 Sender IP reverse lookup rejected

This is the mail system at host qrelay182.mxroute. com.

I’m sorry to have to inform you that your message could not be delivered to one or more recipients. It’s attached below.

For further assistance, please send mail to postmaster.

If you do so, please include this problem report. You can delete your own text from the attached returned message.

<[schinger@xyyz. org](ailto:schinger@xyyz. org)>: host ttc.xyyz. org[64.53.00.102] said: 550 Sender IP reverse lookup rejected (in reply to end of DATA command)

#3

In this case we determined that one of two things will be true:

  1. The recipient server uses DNS resolvers that are not functioning properly.
  2. The recipient server scans all IPs in email headers and checks them for valid PTR.

While we cannot compensate for #1, we can potentially mitigate against #2. We remove some “Received” headers when sending out email, which means the furthest back the headers should reveal would be the cPanel server your email is hosted on. While this should not be checked for a PTR record because that IP does not connect to recipient servers, I can still add one and see if it helps to mitigate. I’ve gone ahead and done that.

#2

WHOIS shows that the client’s domain is in clientHold status … which basically means that the domain registration renewal fee was not paid.

So until they renew their domain, it will not be able to receive email.

#4

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