Under Tools/Account Settings, select an account in the left pane, then note the Outgoing Server (SMTP) drop-down in the lower right pane. The current selection is probably the same as the one with the stored password. If you choose another smtp server, you'll be prompted for the password when you send over that server, and have the option to save the password in Preferences.

To enhance the smtp selection process, there is an add-on:

https://addons.thunderbird.net/en-US/thunderbird/addon/smtp-switch-reborn/

You are right. Thunderbird prompted me the first time a connection to the other SMTP server was established. At that occasion, I was also asked whether I want to save the password for the future.

The reason why I have not seen this before is because my SMTP configuration was not correct before, namely I used SSL/TLS instead of STARTTLS encryption. When I tried to send a test email, the error message was a bit ambiguous, so I thought it refers to the password rather than other configuration settings, which is why I was so frustrated about not being able to change it. I suggest that developers make this more clear in the next version.

Thanks again for your help and have a nice Christmas holidays!

I have to change my outgoing smtp password and Thunderbird does not let me do it. Help please!

What is preventing you from changing it? Go to Options-Security-Passwords-Saved Passwords Click Show Passwords Right click the saved password and select Edit Password.

If that does not fix your issue start your own threads with details of your issue.

The outgoing mail server password is not in the password list.

It won't be until you make contact with the server and Thunderbird is asked for a password. Then you click the box to save the password. That is the only way to save a password in password manager. The fact the password is not shown means you have no need to change anything in Thunderbird.

Now please open your own thread and stop posting to an old, solved one.