Symptoms:
When you attempt to send emails from your account, your email client gives an error message and no new emails are sent.

Cause:
There are several possible causes ranging from the server being unavailable to a problem with your email client setup.

Resolution:
The first step you should take would be to see whether you entered the settings correctly. Even a tiny . can stop your email from sending. Check your authentication setting to see if it's enabled. In cPanel, you can have the server setup your email setting for you or read the steps and compare to what you did when setting up your email client.

Next, check to see if your system can reach the  email servers. If you are running a windows based system use the following steps:

1. Click on the start button
2.  Select the run command option
3. If you are running windows 95, 98,  or ME type command in the box that appears. If you are running windows NT, windows 2000, or windows XP type cmd. If you are  running OS X, open a command shell.
4. In the dos box that opens type  'telnet mail.domain 25' where domain is the domain that is hosting for you.
5. You should see something similar  to the following text if you can connect to the  servers:

Connected to mail.domain.

Escape character is '^]'.

220-We do not authorize the use of this system to transport unsolicited,

220 and/or bulk e-mail.

If you don't see that text then your computer can't reach the servers. In this case, open a command box following steps 1-3 above then type 'tracert mail.domain' if you are running windows or type 'traceroute mail.domain' if you are running OS X. Open a support ticket and include the output from the traceroute or tracert command.

If you can connect to the servers, please open a ticket and indicate what email client you are using, which operating system you are using, and the error(s) if any that you are receiving from your client.