Making changes in the password mail box of Thunderbird may not be the most effective way to change the password. Sometimes, the changes do not take effect. However, there is no need to reset the Thunderbird account as it is possible to reset the password of Thunderbird. For the settings to take effect, the existing passwords must be removed from the password settings of Thunderbird. Removing the saved passwords from password settings of Thunderbird will prompt the internet mail software to ask for the password of the account at startup. Changing the password of an account with Thunderbird can then be done when restarting it.
If you wish to change the mail box password, you may find that Thunderbird does not take into account these changes. If that's the case, there is no need to reset the account, you just have to reset the password!
The aim is to make Thunderbird ask you for a new password for the account when restarting.
In the new window that opens choose the Privacy tab and then the Passwords tab.
Click on Change passwords stored
In the new window, simply remove the password for the account you will not use anymore.
Quit and restart Thunderbird. It should now be OK.