1. Navigate to website https://currently.att.yahoo.com/
2. Select Mail in the upper left corner of screen.
3. Enter your User ID, which is your email address, and Password and press the Sign in button.
4. The following screen will prompt you to send a code to your cell phone to confirm your identity (two factor authentication). Press the Send code button.
5. The next screen prompts you to Enter (the) code. I enter the six digit code and attempt to press the Submit button. I noticed the Submit button is grayed out until the six digit code is entered. Unfortunately, the Submit button cannot be pressed successfully. I can successfully press the Cancel button which asks "Are you sure you want to cancel? You'll have to sign in again and start over." The two options are Yes and No with Yes selected as the default.
Below I have copied all the text from the Web Console and Error Console. Any help in resolving this issue would be greatly appreciated. Until I can resolve this issue, I will have to access my AT&T email from a chrome browser. I would be interested to know if other AT&T email users are having similar issues.