You should use inbound.att.net for an AT&T POP account, and enter a secure mail key instead of the account password.

https://www.att.com/support/article/dsl-high-speed/KM1010523/

https://support.mozilla.org/en-US/questions/1313640

https://support.mozilla.org/en-US/questions/1314254

That didn't help. But, my settings were yahoo.com not att.net (probably shouldn't make a difference. Returned same message. I don't see anything that says/indicates "secure mail key," choices are: Normal password, Encrypted password, Kerberos/GSSAPI, NTLM, and OAuth2. Maybe I really need more information.

If you had a regular Yahoo account, the incoming server would be pop.mail.yahoo.com. But since you have an AT&T-type account, it does make a difference when you use the correct servers, as indicated in the cited link.

The links to this forum explain how you have to generate the secure mail key on the AT&T site and then enter it into TB, where the authentication method must be 'normal password'.

I have 5 accounts that my Thunderbird checks: [email address], [email address], [email address], [email address], and [email address]. The only account that I really get mail on is the [email address], rarely get email on the others, my charter mail on the charter.net account, the meisler.info is an account my daughter set on a server she maintains in SLO or Seattle I probably use once a year.

On 11/12 I collected my email, but later in the day, I was not able to get my email. On my main account. Latter as I tried to following instruction, the other 2 sbcglobal accounts quit receiving mail. I can still get email on the charter.net and meisler.info accounts. All the accounts come through charter.net (Spectrum). I am attaching a pic of the settings I was using before it quit working. I use "unified folders."

As I have been using Thunderbird for 20 years and have many folder arranged and saved emails going back those years. I really don't want to switch to and have to learn something new. As I started with sbcglobal.net, which became att.net, then yahoo.com, now I believe it is "owned" by Verizon. But getting support is impossible.

thank you Wayne Gordon [telephone number]

I can barely make out the text in your picture, but for the sbcglobal account, the server is incorrect. The link I provided above says to use inbound.att.net on 995 for POP accounts, and outbound.att.net on 465 for SMTP.

Remove the sbc passwords from Saved Passwords in Options, restart TB, enter a secure mail key when prompted.

(I have edited out the email addresses from your question for your privacy and security as this is an open forum.)

Dear sfhowes, I know that you are probably very frustrated by my seemed incompetence. But it does not come close to mine with trying to fix this. Again, until 11/12 everything was fine, I changed nothing, and it quit working. I have spent a lot of time on this (s have you) and continue to see only errors. I have attached my current settings after the latest changes. BTW, I saw no way to remove the passwords, but every time I change something it asks me to enter my password and to save to Thunderbird. I am attaching a pic of my current settings. Wayne

Remove the sbc passwords from Options/Privacy & Security/Passwords/Saved Passwords. To view the passwords you will have to enter your Windows user account login and password.

Did you create a secure mail key on the AT&T website? After the passwords are deleted, restart TB, enter the key when prompted.

I am using Thunderbird with 5 mail accounts, including 3 ATT (@sbcglobal.net actually).  On 11/12/2020 in the morning I checked and received my email.  Sometime later in the day, it quit working returning the message "Sending of password for user . ." ". . . did not succeed. Mail server pop.att.yahoo.com responded: Server error - Please try again later."  Since then I have been on forums at both ATT and Mozilla, and now get nothing except different errors.   I believe that I know the original settings, but they still don't work. My time and frustration are at a very high

Would really like detailed directions on the settings that go into Thunderbird and any changes I may need to make to the ATT accounts.

It doesn't seem that you are following the advice offered. Understand that many email providers are eliminating use of account passwords for email client use. Use of one "master" password for everything is considered a very poor security practice.

It's nothing you did that caused your mail to stop downloading, and attempting to reuse your old password will not work. You must create an app/device specific password, or use what is known as an OAuth2 token.

Follow the instructions here: https://www.att.com/support/article/dsl-high-speed/KM1010523/ for your account properties. Note that IMAP is preferred over POP3 and you must choose one or the other.

Then click on the link for client setup. AT&T does not offer Thunderbird specific instructions, but the general steps outlined under Outlook 2016 will work. They lead you through creating what AT&T calls a secure mail key (app specific password).

Make sure you delete your current AT&T password in Thunderbird, and then when prompted, enter the AT&T secure key password.

I spent most of today, and a lot of time in the last few weeks, and it has only gotten worse. I believe that I have done everything suggested. However the instructions are from from clear, and the links to att are at best not useful, sometimes not active anymore, and definitely hard to follow. Now, my spectrum.net won't get mail, and when Thunderbird is running, the pops up a Yahoo window. I think I found out one thing, when trying to set up the account for Imap it would not allow that, the POP message remained. I tried to set up a new account, but that would not connect. Do you have a link, phone where I can pay to get someone to actually talk me through this problem? Otherwise I will try to find another program, but don't want to as 20+ years of emails and addresses are in this, and I don't want to lose them.

I still have seen nothing to indicate a fix for this problem, but do see there are more that are having problem with Yahoo/ATT mail accounts. I kind of wonder if there are those who are just laughing at my frustration. You don't seem to know even if the problem is with Thunderbird or ATT. Yesterday, I did the last thing I could think of, copied the Thunderbird to a different location and completely removed Thunderbird and all that I could see related to it. I reinstalled Thunderbird, no accounts, no nothing. As the auto account installer loaded, it only wanted POP account, changed it to IMAP but that didn't work. Then tried using the Auto install with POP settings, that didn't work. But the good thing is that I guess I can move to a different program. One which I may be able to get actual support.

Yahoo, AT&T etc have changed how the password works. They state and I quote "We’re enhancing the security of AT&T Mail. Soon you’ll have to use either OAuth or a secure mail key to get your email through an app." So now you know what is causing the problem. You are probably not providing what they want. You could say Thunderbird is wrong because you have not set it up correctly. You could say the problem was caused by Yahoo ATT because they changed the Authentication Process. Either way, you need to change settings to how Yahoo ATT state they want.

If using the Yahoo server - imap set up - then instead of 'Authentication Method: Normal Password', you select 'Authentication Method: OAuth2' for both incoming and outgoing.

If using POP and 'Authentication Method: Normal Password' then you must create a secure mail key and use it in Thunderbird when prompted for password.

The images show you have settings ok for pop account set up with 'Authentication Method: Normal Password' . This means you must create and use a Secure Mail Key.

But so far, after showing images of one of your accounts - this was really useful - you have not supplied additional vital information, so it is not easy to understand what you have done or failed to do. You keep talking about no email and recreating accounts. Yes we understand that, but you are not providing any information on whether you have followed any instructions. You may be continuing to do things the old way.

It is a two way communication and from what I've read so far, you have been provided with all information, but you have not confirmed whether you have followed the process. As the same process works for everyone else, we need to know if you are continuing to make the same error or whether you have changed over to the new process.

It is important to do one email address/account at a time because there is less chance of you mixing up the 'Secure Mail Key' which will be different for each email address.

So for each @sbcglobal.net email address; did you do the following process: Q1. Did you use the link provided to create a 'Secure Mail Key' for a specific @sbcglobal.net email address? https://www.att.com/support/article/email-support/KM1240308 Read 'Create a secure mail key' section and write that number down very carefully. It can only be used for that email address/account. Each email address will need a different 'secure mail key'. If no, then do it now.

Q2. Did you delete the password that is stored in Thunderbird for the @sbcglobal.net account ? There will be two lines, once for mail incoming and one for smtp outgoing. Select each line and click on 'Remove'. If no then do it now.

Q3. After, removing the stored password, did you restart Thunderbird immediately ? You need to restart Thunderbird after removing the mail and smtp lines in stored passwords.

Q4. At the prompt for password for that @sbcglobal.net email address did you enter the 'Secure Mail Key' (not the normal password) which you created for that email address/account ?

Q5. Did you then repeat the same process for all other @sbcglobal.net email addresses ?

This process is very specific and requires that you do everything in a specific order.

In addition: Assuming you have done everything correctly and you use ESET please read on: If you are using ESET/NOD32 security/Anti-Virus then probability is very high it is causing your problems. According to their forums, you should temporarily disable SSL until they solve the problem per https://support.eset.com/en/kb3126-disable-ssl-filtering-in-eset-windows-products?ref=esf - the problem is being reported by dozens of users https://forum.eset.com/topic/26517-problems-with-thunderbird-and-imaps/ https://forum.eset.com/discover/

Spectrum: No idea what your server settings were using nor what they should be using as it is based on email address. But here is some useful info.

Server Settings: The following is copied text from Spectrum: Server Settings Based on Domain (@example.com) Charter.net

• Incoming Email Server: mobile.charter.net
• Outgoing Email Server: mobile.charter.net

Brighthouse.com, bak.rr.com, bham.rr.com, cfl.rr.com, emore.rr.com, eufala.rr.com, indy.rr.com, mi.rr.com, panhandle.rr.com, tampabay.rr.com

• Incoming Email Server: mail.brighthouse.com
• Outgoing Email Server: mail.brighthouse.com

TWC.com and any domain ending in .rr.com not covered above

• Incoming Email Server: mail.twc.com
• Outgoing Email Server: mail.twc.com

IMAP is the preferred method that spectrum would like you to use as it does offer a more secure connection. But you cannot simply swap over the server settings - if you currently use Pop and want to change, this would require creating a new existing mail account as IMAP. If your email address uses twc:

• The incoming mail server: mail.twc.com
• Incoming server port: 993
• Connection Security: SSL/TLS
• Authentication Method: Normal Password
• User name : full email address

But if you use POP and want to keep using POP, so this means you can change server settings. POP

• The incoming mail server: mail.twc.com
• Incoming server port: 110.
• Connection Security: None
• Authentication Method: Normal Password
• User name : email address

• Outgoing mail server (SMTP): mail.twc.com
• Outgoing server port: 587.
• Connection Security: 'None' but is worth trying 'STARTLS'
• Authentication Method: Normal Password
• User name : email address

After making changes to Server Settings, you will need to restart Thunderbird.

I completely removed my @sbcglobal.net accounts. I started again, got a secured key and restarted one of my sbc accounts using the secure key. Still won't get my email Note 1 - I can still get email on my other 2 accounts. Note 2 - No one has told me why it quit working in the middle of the day, nor really answered any of my questions. Note 3 - If there is no one at Mozilla that wants to help, or is not able, why not just say so.