SmarterMail suddenly failed to send
Question asked by Yee Qi Chuah - October 8, 2017 at 8:23 PM
Hi, I had used SmarterMail 14 since 2 years ago, My mail server cannot send since 3 days ago, all the outgoing mail pending on pools. i tried to restart the services & restart the server, but it still same. May i know there are any way to solve it?
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For one, something could be suddenly blocking your outgoing SMTP - port 25. You should check into that - it's usually the first thing I check when such a thing happens.
You may also want to check the DNS servers that you are using in SmarterMail. Try changing them to Google's ( and or OpenDNS's ( and servers.
Linda Pagillo
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Office: 703.988.3606

Authorized Reseller of SmarterTools Products
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Do you use an outgoing gateway, or is it just a one e-mail server deployment? Like Paul said, you may want to check the firewall to make sure port 25 is not being blocked now. What happens when you try to send an e-mail from your domain to your domain? (From to This will help show whether it is something in the mail server, or an external factor.
Here's the telnet syntax, from a CMD prompt:
telnet <known-good-smtp-recipient-server (FQDN)> 25 [enter]
One good server to test with, and the full command is:
telnet 25 [enter]
The approximate response from this server should be
220 ESMTP (some of the numbers in that return string may be different)
If you don't get that (if you get a .. cannot connect .. message or some such), you probably have an outgoing email port blocked, either within your network firewall, windows firewall, or it's being blocked by your ISP.
If you do get a good response, then you should check SmarterMail further, and make sure, for one, that your Bindings have not changed.
This assumes that, as Matthew mentioned, you are not using an outgoing gateway; in this case you want to
telnet <gateway fully qualified domain name> 25 <enter> OR
telnet <gateway IP address> 25 <enter> from the CMD prompt.
Also, make sure you have no other SMTP servers running on that Windows server.
You can usually test your SM server's SMTP server directly with
telnet localhost 25 <enter>
(BTW you can then either close the command window or type quit [enter] to get back to the command prompt, leaving that command window open)
Here's how to make sure your DNS settings are generally good (2 examples), from a CMD prompt:
ping <enter> OR
Any non-timeout response means your DNS settings should be OK.

It appears that the problem is not with SmarterMail. Is this in a residential (residential ISP connection) environment?

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