Hello,
I'm sorry to hear that you are having problems with sending email from Thunderbird. The error that you're seeing concerning the timeout can be caused by a variety of reasons. It could be the that your internet connection is blocked, internet is not working at your location, email server is down, etc. You will need to speak with your internet service provider or your mail host (they could be two different organizations). You can also reference our email articles to help troubleshoot your issues where they apply.
I hope this helps to answer your question, please let us know if you require any further assistance.
Kindest regards,
Arnel C.