Follow these steps to access your Verizon-Yahoo mail with Thunderbird (and other email apps):
- Log into Yahoo at https://www.yahoo.com/ on your web browser.
- Hover the mouse over your name and then click on “Settings”, or access Settings using your touch screen.
- Click on “Account Security” (on the left side of the screen).
- Click on “Manage app passwords” (at the bottom of the screen, or scroll down to see it).
- Click on “Select your app”.
- Look at the list of apps and select yours if it is listed. Thunderbird is not on the list, so select “Other App”.
- Type “Thunderbird” into the “Enter custom name” field.
- Click on the “Generate” button.
- Copy the password that is generated. Keep a record of it. You will need to use this new password every time you start Thunderbird, unless you use the Thunderbird master password to remember it.
- Go to Thunderbird and click on “Get Messages”.
- When Thunderbird asks for the password, enter the new app password that was generated by Yahoo.
- The first time that you send mail, enter the same new password that was generated by Yahoo. This is for the outgoing mail server.
- If Thunderbird does not ask for the new password and instead gives an error message, go to Thunderbird – Tools – Options – Security – Saved Passwords… and delete the old incoming and outgoing passwords for the relevant account.
After these steps, Thunderbird will be able to access your Verizon-Yahoo mail again! If you have more than one Verizon-Yahoo account, then repeat the procedure for each account.
I think this procedure will also work for Outlook, iPhone/iPad mail, and other email apps, but I have not tested it with anything other than Thunderbird.
The password created using this procedure is only for Thunderbird (or other email app selected in Steps 5-7). If you use the Yahoo app on a phone or tablet, or access webmail on Yahoo.com, your original Yahoo password will still be active on those other devices.
This is basically the procedure given by Yahoo at https://help.yahoo.com/kb/create-password-sln15241.html