To retrieve e-mail from a remote server you use the Post Office Protocol version 3 (POP3), which is different from SMTP, the protocol used to send mail. When you want to send an e-mail Thunderbird connects to the SMTP server, and the SMTP server responds. The status message at this stage is Connecting.... If the error The message could not be sent because connecting to SMTP server server name failed. The server may be unavailable or is refusing SMTP connections. Please verify that your SMTP server setting is correct and try again, or else contact your network administrator. appears at this step one of the reasons below might be the one that gives you the error:

- You specified the wrong port number. To change this open Thunderbird, go to Tools -> Account Settings -> Outgoing Server (SMTP) -> Edit and enter these settings:

Server Name: mail.afghan-host.com
Port: try with 25 or 587
Check the Use name and password box
User Name: user@afghan-host.com
Use secure connection: NO

- The server is down. This is usually temporary.
- Your firewall is blocking the port. To get pass this go to your Control Panel in Windows, open Windows Firewall. Then go to the Exceptions tab, click the Add Port button and enter 25 in the port number box.
- Your ISP is blocking the port. This often affects port 25, and you can often work around it by using port 587, but details depend on your ISP and on the SMTP server's configuration.

If this still doesn't solve your problem contact the SMTP server administrator at info@afghan-host.com for the exact settings of your mail.