I have this problem that I am aware is kinda common: I can receive emails from the Gmail server, but I can't send any. I followed the Thunderbird configuration procedures from the Gmail settings, and every time I try to send an email, I receive this message:

Sending of message failed.
The message could not be sent because connecting to SMTP server smtp.google.com failed. The sever 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.

Is this related to Thunderbird or to Gmail as such? 'cause one of my friends experienced the same problem with Windows XP as OS and he gave up... I mention that I have Linux Suse as OS.

What should I do? Thanx!

Make sure your ISP is not blocking outside SMTP servers that are not their own. They at times will do this to prevent people to send spam. Also, since your on your ISP's network, they might require you to authenticate on the google servers to send, etc.