outlook failed 24 hours ago and 6 hours with ATT ASIA, USA support accomplished nothing

Can you provide the full error message?  There's usually an error code for most Outlook errors.

You said you generated the SMK.  When did you do this, once the problem surfaced or do you mean you had one prior to all of this.  I ask because we've seen existing SMK's fail and you have to delete those and create a new one.

And finally, have you tried these servers instead of the att.net servers?

imap.mail.yahoo.com

smtp.mail.yahoo.com

Tony, Thanks!  I restored the C:\ partition, 39GB from my August Macrium Image and updated the secure mail key. works perfectly now. Never know what blew it up.  microsoft update likely kill Outlook.  Lots of Office 365 stuff on C: drive that I don't want, cannot stop MS blote SW.  Delaying all MS updates. for a while.  MS says my pc is not elegable for Win11 "upgrade", Yeaaaaa These outlook  settings work.  Cheers

Excellent news! 

I don't think it was an update from Microsoft (although heaven knows they do cause more damages than they should).  I've seen the SMK get, oh, let's call it "corrupted", on an older Windows machine that doesn't get updates any more.  Something has to be doing that on AT&T or at Yahoo.

The internet is a moving target. Between the crooks trying to steal money and  antivirus venders trying to stop it, Microsoft changing from software sales to a subscription model,  the average PC user walking through this minefield and mountain of stress just staying connected.  The internet is a dangerous place and becoming more so.   It's Every man for himself.

Att could do a better job supporting USA customers by telling them exactly what are the server settings that work locally especially before making changes.  I have 4 sets of email server access settings collected during this aggravating experience.  The secure mail key requirement and it's roll out should have been better announced/broadcast. 

In last two months ATT now denies web page logon if VPN is enabled.  A tunnel setting must exclude ATT.COM to access my account now.   No prior announcement.. That bit of information was also unknow and no ATT support person (800 288 2020) ever provided any help on that problem. 

There is also no way to contact ATT via email so getting accurate documented setup details and tracking problem support is impossible except for this volunteer Community.  The consumer gets short end of the stick from ATT.  After 40 years as a USA ATT.com customer I am looking for better USA supported Internet access.  Thank you for your help.  Regards jdb

After 40 years as a USA ATT.com customer I am looking for better USA supported Internet access.

Heh, good luck with that!  There's a reason AT&T feels they don't need to do a better job than this totally unacceptable excuse for a support system.  That's because none of the other major ISPs is any better at all.

Tony,  you are likely correct but I will keep looking anyway.  Good luck to you. Kind regards, jdb 

You too!  If you do find one that has even close to acceptable service, come back and let us all know.