Thunderbird does not send mails: How to proceed

If Thunderbird does not send mails anymore, it is usually due to incorrect settings. Often, your firewall also blocks an outgoing connection and therefore prevents you from sending mails. However, you can address this issue and quickly get rid of it.

Thunderbird does not send mails: Is it the SMTP server?

The SMTP is the outgoing mail server. If there are incorrect settings for this server, no more mails can be sent.

1. Start Thunderbird and press [Alt] to open the menu bar.
2. Now click on the "Tools" entry and select the "Account Settings".
3. Bottom left you will now find the item "Outgoing mail server (SMTP)". Click on the entry and check the settings.
4. Make sure that both the port and the server are specified correctly. If they are incorrect, no mails can be sent.
5. You can find the correct values on the information page of the hoster via the search by entering "SMTP".
6. When you are satisfied with the settings, click "Apply" or "OK".

Thunderbird does not send mails: firewall or antivirus program?

1. Es kann durchaus helfen, vorübergehend Ihre Firewall und die aktiven Antivirenprogramme zu deaktivieren.
2. Nicht selten kommt es vor, dass einer der beiden Dienste eine ausgehende Verbindung blockiert und daher keine Mails zustellt.
3. Stellen Sie in der Firewall zusätzlich den Port auf 587 oder 465 um, da diese meist nicht blockiert werden.