One email acct can receive but not send; help troubleshooting


Well-Known Member
Sep 26, 2006
cPanel Access Level
Root Administrator
I have a hosting client that has several email accounts, used in several offices. One of those offices is having a problem in that they can receive emails, but when they send, nothing happens; it just tries to send for 2 minutes before timing out.

This office isn't local to me, so I can't see the computer, but did try working with them over the phone. After an hour of going over every setting, though, I couldn't find anything.

Some notes on the situation:

1. I did get an email from cpHulk that they had made multiple login attempts to:
[email protected]

They're using Outlook for email, and confirmed that the username listed is just [email protected], so I don't know why the report showed the

I had them remove the, with the thought that maybe Outlook was automatically sending the rDNS, but that just gave them an error that the username was incorrect.

2. In Outlook, if they click on "Test" in their settings, the test is successful.

3. They can send and receive emails through Webmail with no problem.

4. Just to be safe, I whitelisted their IP in cpHulk, and made sure that it's not blacklisted. I also turned off the server's firewall for testing, which had no impact.

5. The client turned off their Norton Antivirus (or, more correctly, they temporarily disabled it) and their Windows Firewall, but this, too, had no impact.

6. I had him change the SMTP port from 25 to 26, but that also had no impact.

It apparently just started yesterday, and no one else on that server has reported a problem, so I think it's just this one guy. The fact that he can use Webmail makes me think that it's restricted to his computer or internet (although his IP swears it's not on their end), but the fact that the Outlook "test" is successful is confusing.

I also suspect an issue on my end because, as of yesterday, I started getting numerous reports that tailwatchd was failing and restarting. I'm not entirely sure what tailwatchd is, but the fact that both problems started yesterday makes it suspicious.

Can you guys suggest what else I might do to find the problem?


Well-Known Member
May 19, 2011
cPanel Access Level
Root Administrator
Firstly, in Outlook have you selected "My server requires authentication"?

Have you done a telnet from his machine?

telnet 25
What is the output?

The logs should also hold a clue.

Through SSH run:

tail -f /var/log/exim_mainlog

In CPHulk, have you Purged the brutes list and removed the 2 week ban for that IP?