Resolved SeaMonkey e-mailing suddenly went bad

My wife has a laptop upstairs and I have a desktop downstairs in our home, connected via wi-fi using AT&T U-Verse as our ISP. We both use SeaMonkey as our browser and e-mail client. Same e-mail address, just different sender ID's. Until about noon today, everything -- including SeaMonkey e-mail operations -- worked fine on both systems.

Later this afternoon my wife complained she couldn't send an e-mail. I checked her laptop, couldn't send anything, got an error message: "Login to server smtp.att.yahoo.com failed ", then the program froze. Rebooted, e-mail client warned: "Sending of password did not succeed. Mail server smtp.att.yahoo.com responded: invalid user/password ". Tried another test message, unsuccessful. Same warning. I could get on-line and reach any Web site I wanted, just couldn't send e-mails.

So I went downstairs and tried with my desktop to send a test e-mail to myself. Same failure, same warning messages. Web browsing fine, just no e-mailing.

I phoned AT&T U-Verse tech support, spent an hour trying different things, including trying to get a password to work on www.att.yahoo.com (I think we tried that on both SeaMonkey and IE.) He sent a test message to me, I didn't get it. Then I logged onto ATT Yahoo Mail and it didn't like my password. He changed it to a different one, that worked and I saw 7 new messages, including his test message. Tech support guy couldn't find anything wrong at his end, wasn't very familiar with SeaMonkey, advised me to get help from them, and we hung up our phones.

After that I went up to my wife's laptop and first tried the usual SeaMonkey e-mail routine. Failed. Same warning messages. Logged onto Yahoo Mail with the new password, and got those 7 messages plus some newer ones.

So what's the likely explanation for SeaMonkey's e-mail function suddenly going bad? Both computers have all hardware and software up to date, including malware programs, and everything else seems OK except for this e-mailing problem appearing out of nowhere. Any ideas?

 

Problem fixed!

Each time I tried to send or receive an e-mail using SeaMonkey, I'd get a warning that SM didn't recognize my password. In that warning box was a button "Enter new password" (or some such wording), and today I clicked on that button and entered the most recent password I'd created while on the phone with AT&T tech support last night. Bingo! Nineteen new messages began arriving. Additional tests to send and receive e-mails all worked, both on my wife's laptop and my desktop.

To clarify one point, every time I tried to find a password that would work last night, I was doing that at AT&T's Web site. Today I did it while using that SM new password button -- within the SM program -- and that's what made the difference.

So, problem solved. Why it cropped up in the first place, I still don't know, but at least now we're back to e-mailing normally.

I'll mark the thread as Resolved.