When you start Thunderbird it should ask for password as it attempts to access server to get incoming mail. Enter password and select the checkbox to remember password before clicking on OK.

Does that work ?

Toad-Hall - i appreciate your posting! Thank you so much for taking the time to do so.

However i decided to just use a logins.json file from one of my backups from several months ago. Although the passwords are encrypted, the rest of the file provides enough info to determine that it might be useful. So, i just renamed the current file and copied the older one and ran TB again and there they were! Easy peasy!

Have a beautiful day and please stay safe! And, of course, thanks again ever so much!  :)

Thunderbird on my Win10 laptop has two accounts, one for verizon.net (a legacy AOL account from before Verizon sold that function to AOL) and one for a Mail.com account. I have used both for several years, and have many messages in different Thunderbird folders under each account. They worked until 8/7/21, which maybe is when the last Thunderbird update occurred. Now only one works

Under Tools/options/passwords/saved passwords, it shows the same Mail.com password for both pop and smtp; But there is no password for verizon.net, for either pop or smtp, and I cannot find a way to add those.

I can send and recieve email with Mail.com, and move emails into and out of its folders.

But I can not send or receive with the verizon.net account. When I try, I get a popup window which says to Enter your password for jv26 on smtp.verizon.net. But Thunderbird will not accept any password for verizon.net, not even the one for aol.com. When I try to send any email, it shows Connected to smtp.verizon.net, but times out. I also get some variation of this: Sending of password for user jv26 did not succeed. Mail server pop.verizon.net responded: [SYS/TEMP] Server error - Please try again later.

I can send a message to my account @verizon.net from the Thunderbird Mail.com acreen  or from a mail.aol.com screen, and it shows up on my aol.com webmail inbox screen, but not on the Thunderbird verizon.net screen.

Thunderbird will not allow me to add a verizon.net account, as a way to establish passwords for pop and smtp. It says that account exists, but will not send from it or receive email into it.

How do I re-enable sending from and to the verizon.net account in Thunderbird, without destroying the emails in the existing verizon.net account folders? How do I re-establish passwords for verizon.net without destroying the passwords for the Mail.com account?

I do not have the backup Fred referred to.

The AOL verizon Yahoo folk decided to change things and now require app specific password.

Some info: https://help.aol.com/articles/allow-apps-that-use-less-secure-sign-in

Have you created an app specific password? If no then create one. Here is a link to the info on AOL webpage: https://help.aol.com/articles/Create-and-manage-app-password

When thunderbird tries to access server, it will ask for password: Enter the app specific password and select the checkbox to allow Password Manager to remember the password, then click on OK

Please note: do not enter the normal password - you only use the normal password to logon to webmail account.