pop.att.yahoo.com server error

Thank you ACE-Expert! Problem Solved! The Digital Assistance Center (877-273-2728) told me to change the Thunderbird Server Setting from pop.att.yahoo.com to inbound.att.net

You asked "Why are you using pop.att.yahoo.com in the first place?"  Maybe this is due to the old adage "If it's not broke, don't fix it."  We are using yahoo servers because when the the accounts were set up, this is what we were told to do.  Ever since then, no communications received that this should be changed.  When did it become known that it was now inappropriate to use yahoo.com servers?

@DaveinNC

When?  I would say about the time it signed up for your att account and occasionally ever since then?  I've only had the att internet/uverse service for 9 years.  But when I joined I made it my responsibility to find the server information att, not yahoo, documented for the att email server settings.  That's what I used.  If the email "broke" one of the first thinks I would check are the documented att settings again in case they change.  Can't remember if that ever happened though.

When it comes to the knowing about att's documents att is very negligent about posting announcements of new articles (or updates to existing articles).  But the att server article does exist and hasn't changed for quite some time. [FWIW, another, almost as important email related document is the one about OAuth and the secure mail key.  It's tucked away here.] 

IMO given the situation it's up to you and I to "keep up".  And in the case of the server info, the email service has no obligation to continue backward compatibly with the "old servers".  If they work, fine, your lucky, but you are potentially living on borrowed time.  This is always been my philosophy about email servers and nothing is going to change it.

Feel free to use the yahoo servers if they work for you.  But you are in no position to complain when or if they don't.

OK, useful response.  When I signed up years ago, I did determine that the requested settings at that time were for yahoo.com.  You're fortunate that you're daily in the AT&T loop, but I've never had the time to continuously ride herd on AT&T support website to see if anything's changing.

What baffles me is why it is even possible for someone to send me mail to xxx@att.net and I can get it fine using the yahoo server (so far) and I'll get it OK if I change to the inbound.att.net server.  Does this mean AT&T is maintaining all my e-mail on both servers simultaneously?  (When I do change one client to inbound.att.net, will AT&T take note of this and disable all my other yahoo-based clients, forcing me to update all of my clients at the same time?)

Re _xyzzy_ comment "The only reason you would need to search out the server info is the first time as I said previously and then when something "goes wrong" with your email access.  No need to "ride herd".

I guess I failed to make myself completely clear.  When I signed up years ago, I did determine the requested server settings, which at that time were for yahoo.com.  And ever since then nothing has ever gone wrong.  But obviously I do need to "keep up," as you put it, as that's the only way to learn about these "new" server settings, and for example, the looming OAuth situation.

Thank you for your detailed speculation about the data bases and why two sets of servers can be at play concurrently.

@DaveinNC

And ever since then nothing has ever gone wrong.  But obviously I do need to "keep up," as you put it, as that's the only way to learn about these "new" server settings,

Or, as I said, just wait until what you are currently using fails.  Then hunt the server info down.

...and for example, the looming OAuth situation.

Not sure what you mean by "looming".  It's already here since last February.  OAuth was "announced" (use that term loosely of course) since this article came out (the one I mentioned in post 5) in February.  And since it never made clear (to me) what OAuth they were talking about (OAuth1 and OAuth2) the easiest thing to do is to use the alternative they present, i.e., the secure mail key.  And that's what I have been recommending to anyone using email client apps (e.g., Thunderbird, Outlook, mobile email client apps, etc.).  It adds a added degree of security to devices using email client apps.  They are simple enough to create (that article has a link on how to create one) and it's trivial to change the clients to use it in place of the account password.  Using OAuth on the other hand may or may not work in all email clients, depending on which version of OAuth they support and/or whether the client supports it for both POP and IMAP.  I never really dug that deep into OAuth but I know my Thunderbird doesn't support it in any form for POP which I am using.

By "looming" I meant "looming for me."  I have two desktop PCs that use the (supposedly) non-compliant Window Live Mail, have not switched them to new secure key, and they continue to work fine.  So far.  I plan to get a secure key and have it on hand for the day OAuth strikes me.

I plan to get a secure key and have it on hand for the day OAuth strikes me.

Apples and oranges.  Use the secure mail key or change your authorization to OAuth along with your account password.   Regular account password should still work unless or until "they" enforce that these security methods must be used.