As of the morning of 5/29/19 my att.net email account no longer works. I have since tried sending emails to that account as well as a sub account and both are bouncing back with Addresse Unknown.
I don't know if this is some att/yahoo issue or what.
I have had this account for over 20 years and am in a real bind not having access to it. Additionally, I am about to go to sea and will have a very difficult time trying to continue to troubleshoot at that point.