Is there any possibility to reenter passwords for the exisisting accounts in thunderbird?

Thunderbird will prompt you for a password when it's needed.

Even if I close and open thunderbird again, it just says Thunderbird wasn't able to connect but no window requesting to enter password appears.

So you don't even get to the point where Thunderbird would prompt you for a password. There are multiple potential reasons why not:

• your Internet connection is not working - can you login to your account via webmail?
• your account settings are wrong - check with your email provider about the correct settings.
• your anti-virus software is interfering

What is the exact error message?

What is your anti-virus software?

HI, thank you for answering!

your Internet connection is not working - can you login to your account via webmail? - I confirm working your account settings are wrong - check with your email provider about the correct settings. I did a switch from aruba to siteground. I need to enter the new passwords, but the panel "sAVED PASSWORDS" is empty and I can't follow the help article. I already changed the settings for the new provider (in and out email settings) your anti-virus software is interfering - Windows security is installed

I already changed the settings for the new provider (in and out email settings)

Note, you're not supposed to modify an existing account, if this is what you did. Create a new account for the new server.

Windows security is installed

If the problem persists, try to start Windows 10 in safe mode with networking enabled.