Is the authentication method on the incoming and outgoing servers OAuth2? If it isn't, make the change to OAuth2, accept cookies in Options/Privacy & Security, remove passwords from Saved Passwords, restart TB, enter the account password in the OAuth window when prompted.

https://support.mozilla.org/en-US/questions/1344702

That helps, but...there is no "OAuth2" setting in Outgoing Server settings. There's normal password encrypted password Kerberos/GSSAPI NTLM

Any of those work?

Is this an AOL account using imap.aol.com or pop.aol.com and smtp.aol.com, or a Verizon account accessed through the AOL website or verizon.net servers in TB?

https://support.mozilla.org/en-US/questions/1344702

The latter, I guess. Incoming are pop, outgoing are smtp verizon.net servers.

Verizon accounts have to use an app password in TB, as explained in the link I posted. TB supports OAuth2 for the *.aol.com servers, but not the *.verizon.net servers.

I see now why the info didn't seem quite relevant to me, thank you.

So...what is an "app password"? And how does it apply to my accounts when they are based on an AOL system at AOLmail, which requires separate passwords?

Also, why did only two of my accounts keep asking for passwords they wouldn't accept, when the other three did not?

The link I provided includes a link to the AOL site about app passwords, and explains how to use it in TB.

Was this the link to the two-page MozillaZine thread? I see something about going to AOL to find something about generating app passwords.

Does this mean, the passwords I worked on for years to stay memorable and still be hard to crack, are no longer something I can count on using?

Sorry, I posted the wrong link. This is the correct one:

https://support.mozilla.org/en-US/questions/1344702

The Verizon/AOL policy now is that email clients like TB must use app passwords if OAuth2 is not supported.

I still don't understand. Does this mean I am going to lose my old passwords? I wrote them to make them easier for my wife to remember. I use a desktop, and Thunderbird, she uses an iPad, and I have a Kindle I have been putting off installing two of my email accounts onto, once I got this desktop mail confusion solved first.

Does this mean, we will be restricted to a single, impossible-to-memorize string of characters that will also be used on both tablets, for different email accounts?

This is the third time I've gotten that link from 1:36pm in my email inbox while I've been on a browser waiting to see if you can answer my question. Am I going to lose the passwords that have made so much sense to the both of us in different uses besides a desktop Thunderbird program?

Is AOL going to remain intractable about this?

This is the fourth time I've been (I thought) patiently waiting for an answer.

You still need the account password to access the account through a browser, as the app password is only for non-browser access. I don't know about iPads or Kindles, but my AOL account on my phone requires an app password, so you probably need one for your devices. With TB, once you enter the app password the first time, check the box to have it stored in Saved Passwords, so it will be applied automatically.

Had a tech guy in here yesterday, we did get the app password from AOL Mail, put it in Thunderbird. Did not solve the problem, still can't access the problematic two sub-accounts in TB. Re-installed one of the accounts using the app password as the account's individual password, that didn't work either.

My wife's AOL mail account still comes into Thunderbird, and does not need to enter the new app password onto her iPad, it still comes in fine on that.

The two sub-accounts that didn't work in TB still work on AOL mail. You can send a test to them, and they show up on webmail. TB still doesn't accept their passwords. The other three accounts work fine in TB.

AOL tech support solved the problem in a remote session.