Mail sent from our server is bouncing from certain domains - this does not happen when sent from a back up IMAP based email set up through another domain and web host.
Domain bounces include hotmail and gmail but also well.com and rnib.org.uk
A sample error message is…
“Router: Failed to connect to SMTP host ITFORCHARITIES.CO.UK because : Remote system no longer responding”
and …
“Router: Failed to connect to SMTP host RNIB.ORG.UK because : The server is not responding. The server may be down or you may be experiencing network problems. Contact your system administrator if this problem persists.”
As i say above the message is not true - both domains receive email from the back up IMAP send
Subject: Re: Sent mail bouncing
Hi Andy,
Please check the TN below to apply the Debug parameters to identify a some issue:
Title: Collecting data for Domino SMTP mail routing issues
Doc #: 1454020
URL: http://www.ibm.com/support/docview.wss?uid=swg21454020
Best Regards!
Subject: Sent mail bouncing
There are a number of reasons that messages bounce. You can enable SMTPClientDebug=3 (using the set config command "set config SMTPClientDebug=3) to get more information as to why messages are bouncing. That is considering Domino is your mail gateway routing out to the internet. Some reasons why you would get rejections… lack of PTR records, SPF records, Black listed, DNS returning an A record instead of an MX record. Aside from the debug, you can also telnet to the server. I would suggest doing so from the server that is having an issue sending to see accurate reasons why. Here are steps on how to telnet to port 25 from your Domino server → http://www-01.ibm.com/support/docview.wss?uid=swg21568052
You can also run some diagnostics from: Email Server Test - Online SMTP diagnostics tool - MxToolbox
And if all else fails, give a call to IBM Tech Support.