Invalid or expired SS certificate of att.yahoo.com:995

For years I have not had any issues with my email setting on my phone using:

I have always used pop.att.yahoo.com

smtp.att.yahoo.com

SSL turned on

port 587 and port 995

Now, I have errors popping up cannot verify server identity... certificate not trusted expires 12/9/16, 5:59 PM.  Unable to verify SSL server.

Now, I can't use email on phone.  This is my main source of using my email as I do not use a computer.  Of course, I can log into email perfectly on a computer. 

Of course, this e-mail was set up as I have had DSL with ATT for years. 

Did Yahoo change email settings? Server settings?  Change settings to where the above information is no longer exist? 

I appreciate an answer to my problem.

Thanks in advance.

"Internet Security Warning"  / "Security Certificate expired and cannot be verified"  / "Issued to pop.att.yahoo.com / "Symantec Class 3 Secure Server CA – G4" / "valid 12/8/15 to 12/9/16" ?? / We check email daily and have not had a problem until now and get the same message on 2 different laptops with both using Windows 10 and Microsoft Office 365. I have checked the Clock on both computers and the current time and date are correct. I have checked with MS and they say it is not with their software; and all updates are up to date. I have also been using AVG for years and their Internet security is up to date.

THis may help you: https://www.att.com/support/article/u-verse-tv/KM1010523/

I am having the same issue. It started today, February 1, at approximately 1:40 pm.

It is not an Outlook problem - it is strictly an ATT/Yahoo issue. Please fix this!

Has anyone figured out what the problem is?  Was something phased out?  Do we need to update settings?I tried changing the pop settings.

Unfortunately neither of these links have anything to do with an invalid SSL certificate.  The problem appears to be on the pop.att.yahoo.com outbound server.  Who is responsible for keeping the SSL certificate valid?

Just getting this cert error now. expire date is 12/8/16 why am I getting this now? how to get rid of it?

Hi Curious-cat, thanks for your tip and I "verified my email client server settings" as the link recommended and they are up to date.; So there must be another problem. Note, we have been using this server setting since 2014 with no issues till now. If you think of another idea please pass it along.

Verify your email client server settings

Me too.  With  Yahoo, I am not making an exception.