I have a client where some of their emails, including some email from me bounce back with a smtp; 550 code. There doesn't seem to be any pattern on which emails bounce and which go through. One of their domains the email is hosted by the web host, and the other domain names the email's hosted by G Suite. The problem seems mostly limited to the domain hosted by the web hosting company, but I'm trying to get that clarified. The client is in another country so communication isn't always easy.
Message not delivered
There was a problem delivering your message to [email protected]. See the technical details below, or try resending in a few minutes.
The response was:
550 "The mail server detected your message as spam and has prevented delivery."
Final-Recipient: rfc822; [email protected]
Action: failed
Status: 5.0.0
Remote-MTA: dns; example.com. (192.0.2.20, the server for the
domain example.com.)
Diagnostic-Code: smtp; 550 "The mail server detected your message as spam and has prevented delivery."
Last-Attempt-Date: Wed, 21 Mar 2018 00:32:19 -0700 (PDT)
They opened a ticket to their web host who responded back:
You may have Malicious scripts on your server as your server IP has sent emails to SPAM Traps at least twice in the last week. I have therefore asked the Cloud Support Administrators to verify if that is true.
If they do find so we will tell you that to correct this issue you will need to find a third-party service that specializes in cleaning sites of malware. We normally recommend a third party provider called Site Lock.
Why would something like this cause some INCOMING email (seemingly randomly as some email gets through some does not) to be marked as spam and bounced? I would think a problem such as the one described above would affect OUTGOING email. There's something I'm not understanding here.
They originally retained me to help them because OUTGOING emails were going to the spam folder. I noticed their ISP (not their email host but the IP addresses of the ISP showed in the headers) was on multiple blacklists. They said the ISP wasn't good and switched. That alone seems to have solved the outgoing email problem, but then this weird problem of emails sent to them bouncing back started happening.
I thought the ISP's bad IP addresses were affecting their deliverability, which makes sense but is also strange because you'd think the IPS, which just happens to be how someone is connected to the Internet would not affect email deliverability. The ISP was not hosting their email. I don't quite understand why the ISP would affect email deliverability but it seems like it does. Why would someone's ISP's IP address rep affect their deliverability if they host their email elsewhere and use the ISP just to connect to the Internet? It's a separate issue than the one above but still puzzling.
0 Answers