What version are you running?

38.0.1

Start *Windows'* safe mode with networking enabled - win8 http://windows.microsoft.com/en-us/windows-8/windows-startup-settings-safe-mode - win7 http://windows.microsoft.com/en-us/windows/start-computer-safe-mode#start-computer-safe-mode=windows-7 - XP http://www.microsoft.com/resources/documentation/windows/xp/all/proddocs/en-us/boot_failsafe.mspx

Still In Windows safe mode, start thunderbird in safe mode - http://support.mozillamessaging.com/en-US/kb/safe-mode

Does problem go away?

this did not fix problem. I did find further that it only happens on the first email I try to send after starting Thunderbird and only on that specific account. Once it fails I'm good to go until I shut down and restart, then it times out on that one server again.

Further to the problem above. I noticed when I start Thunderbird the first time I hit GET ALL MAIL all my mail accounts download but this same account having the send problem. If I hit again it will download.

So something is happening on the first send and receive for this account after starting the program.,

I should also add I have an identical setup on another computer and it's NOT having the issue.

Is this with an exchange server?

Wayne Mery said

Is this with an exchange server?

No comcast.net