Have you rung you provider and confirmed with them the connection details you need to use? This is not a guessing game. THey set the criteria and then you configure your mail client according to their requirements.

In this instance it may well be that AOL have moved to requiring oAuth2.0 authentication. But as I am not a customer of Verizon I really do not have the same level of access to information as you do.

Already contacted Verizon/AOL no changes in authorization. However after lots more experimentation I found the issue but not sure if it is a Thunderbird or Verizon change. I have my own domain and email and forward mail to Verizon/AOL then view respond on Thunderbird. ( There are good reasons) My settings, in Thunderbird are; email address ( my verizon email address) and reply to address (my domain email address). Once I change both to verizon/AOL address where I am sending message from it works. This changed just yesterday as the two email addresses have been different for several years. Now to figure out which changed and workaround. Is Thunderbird requiring these two addresses be the same.

flybob said

Is Thunderbird requiring these two addresses be the same.

Thunderbird offers an option because it is optional. However you have to remember you are dealing with Yahoo.

Verizon are basically merging all mail into yahoo and it is not smooth sailing. Yahoo is a poor mail service provider prone to unilateral decision based on nothing and a refusal to engage with anyone about changes. If they announce them at all.

Thank You. I thought Verizon moved their mail service to AOL. Maybe another move I was not aware of. Might solve questions from others as making both addresses the same solved the problem. After the holiday, I will move everything to my domain mail server and interface that with Thunderbird.

Have a great Holiday bob

Verizon bought both yahoo and AOL. it appears from the outside that everything is being consolidated on the yahoo systems. but the reality is information of a real nature is almost totally unavailable. What information is available is so wrapped in marketing spin as to be just about unintelligible.

Flybob, I'm glad you resolved the problem. You started this thread after you responded to my thread ("Sending Mail Hurdle: "Mailbox unavailable") on the exact same problem, and was advised to begin your own thread by Christ1.

After you came upon the magic solution, why did it not occur to you to return to the thread that played a part in helping you to resolve your problem? I had to arrive at your very same solution, but it took me six more days to do so, after you had arrived at yours.

It Occurred to me, but I was traveling and did not have access. I believe based on the responses to your problem, you had a virus protection issue whereas my issue appears to be an unannounced change in the way AOL/Yahoo required outgoing server configuration. If you are using AOL email they now appear to require the from and reply to addresses to be the same. This is unconfirmed, but making the change made it work. PS: in the process of moving away from AOL/Yahoo where I was sent when Verizon dumped email.