Thunderbird does not send mails: you can do that

If Thunderbird no longer sends emails, this may be due to incorrect settings or a blocked connection. We'll show you how to solve the problem.

Check SMTP server: Thunderbird does not send emails

If you press the [Alt] key on your keyboard, the menu bar opens at the top.
Select the "Account Settings" under the "Tools" category. Alternatively, you can right-click on the relevant account in the bar on the left and select "Settings".
Click on "Outgoing mail server (SMTP)" at the bottom left and check the settings.
Especially the "port" and the "server" are often typed incorrectly. Mails should be sent again with the correct data.
Tip: You can find the correct settings via web search with the name of your mail provider and the keyword "SMTP" (eg "web.de SMTP").
Now click on your email address at the top left and check the "Outgoing mail server (SMTP)" here too.

Deactivate your anti-virus software for a short time and switch off the Windows Firewall. Your outgoing mails may be intercepted here.
Send a test email and check whether it has arrived. If the delivery is successful, you must open the respective port in the firewall.
Port 25 is often blocked. If possible, switch to port 587 or 465. Which ports work depends on your mail provider.

In the next practical tip, we will show you how to protect Thunderbird with a password.