cannot send or retrieve emails
I did an update on my Iphone 6s and since then, it is hit and miss if I can obtain or send emails.. The error I keep getting is "the mail server "imap.mail.att.net" is not responding. Verify that you have entered the correct account info in mail settings". When I get the pop up to enter my password I do and it keeps saying incorrect but that is the correct password. I get my emails automatically on my phone, I don't have to put in a password. I have not changed my password. It will send and receive emails sporadically without me doing a thing so I don't understand the problem. What can I do to expedite getting this fixed so I can send and retrieve emails on my Iphone?