how can I reestablish my Att.net account in Mac mail after I have deleted it.
I changed password on Att.net Yahoo email service that I am using on Mac mail. Once that was done I could no longer receive emails on Mac mail. Contacted ATT Yahoo tech service. Following directions I removed ATT Yahoo mail account and then tried to reinstall it. ATT Yahoo accepted user ID and password but when it requested two step authorization, I entered the 6 digit number and received message 'Authorization failed'. Tried several times and received same message. ATT Yahoo agent helped me selected a secure email code to enter in for authorization. It also did not work. ATT Yahoo mail is accepting my ID and password because I am receiving emails on my iPhone stating a New sign in on Mac OS X. It is Mac Mail that is blocking the two step authoriztion that will set up the ATT Yahoo account. Help
iMac 27″, macOS 10.15