See https://support.mozilla.org/en-US/questions/1359090

This did not solve my problem.. I tried both server addresses, and have the same problem with both.. I have to keep going to AOL security and get a new one time password for outgoing mail to work, and it also screws up my outgoing mail on other devices.

I have to keep going to AOL security and get a new one time password for outgoing mail

I don't understand this. What are you doing that you're prompted for a one time password? With OAuth2 authentication, which you need to select on in your Thunderbird account settings, your main account password is supposed to work.

Are you using any kind of 2-step verification?

Are you trying to enter an app password?

I don't know what OAuth2 is... all I know is that i've been using Thunderbird for my mail application for years, but when they stopped handling mail directly and changed it over to AOL, the system sometimes fails, and all of a sudden the password stops working. In talking to AOL, this is resolved by going to my AOL account, going to security, getting a new one time password for outgoing mail, and applying it. If it ever fails again, repeat the process. Once I bought this new laptop and tried to set up mail, I was told by AOL that for a NEW product, THEY had to set up the mail, so after I signed up for monthly tech service, they took control of the laptop and spent hours trying to solve the problem, finally leaving me with the suggestion that I go to Best Buy Geek Squad, and have the laptop "properly syncronized" with Thunderbird. I did so, the BB second level tech guy took control of the laptop and spent SIX hours trying to solve the issue, finally saying the problem was with Thunderbird, and I should get a Geek Squad rep to come to the house and try to solve it.. which is now scheduled for Oct. 16th... with little hope on my end. Right now the problems with the desk top, that occurred during this process, seem to have gone away and mail is working.... mail on my old laptop, or new laptop, however, is not. (Since AOL handles Verizon mail, my mail comes into my AOL account in parallel with Thunderbird, and that mail continues to work with no problems.)

I forgot to mention.. my Thunderbird verizon outgoing mail password is normally the same as my AOL sign on password.. that is how AOL has Verizon mail configured.

At the top right of the Thunderbird window, click the menu button > Account Settings

In the left pane select 'Outgoing Server (SMTP) at the bottom of the list. Select the SMTP server for the Verizon account - Edit

Make sure the following is set: Server Name: smtp.aol.com Connection security: SSL/TLS Authentication method: OAuth2

Try again to send a message.

If it still doesn't work, please post your Troubleshooting Information. At the top right of the Thunderbird window, click the menu button , then select Help > Troubleshooting Information. Press the "Copy text to clipboard button" and paste the information into your reply.

First, I cannot get this email from you on the laptop, since mail doesn't work.... I did go to the laptop and try to do what you ask, but it does not allow me to enter any authentication method other than the following: No Authentication; Normal Password; Kerberos/GSSAPI; NTLM.

First, I cannot get this email from you on the laptop, since mail doesn't work

This is a web forum, not a mailing list.

I did go to the laptop and try to do what you ask, but it does not allow me to enter any authentication method other than the following:

You need to set the 'Authentication method' to 'OAuth2'. For this option to show up in the drop-down menu you do need to adjust the outgoing server as described above. Did you do this?