Windows 10: Mail is not accepting my correct att.net login for email

Suddenly, Mail is not accepting my password for access to my att.net email. I've Fix, Delete, Add the account. No joy. I am able to login to att.net mail with my credentials. Please explain why I can't do this.

:)

 

Windows Login Email

• Go to "Settings" app, then click Accounts
• Click the Link for "login using a local account" and follow the steps through
• Go back to the same place and now link again to the correct/new email address.

 

Move from Mail to ATT/Yahoo

My W10 Mail is fed by Yahoo but Mail always lags behind so I want to use ATT/Yahoo as my email. How do I make this change?

 

How can I import my ATT email contacts into Microsoft People/Mail App?

I've successfully got the MS Mail app to sync and work with both my ATT email account (run by Yahoo) - but my ATT Contacts/Address book did not automatically sync with Mail. So I went to the MS People app to manually sync the ATT contact list into People
- which should then work with MS Mail. However, when I open People, open Settings and go to Add an Account, the ATT email account does not show up as an option. My Gmail account shows up but not my ATT email account - even though MS Mail sees and is working
with my ATT email account.

Anyone have an idea as to how I can get the People app to "see" my ATT email account (like MS Mail already does) and get those ATT Contacts imported/synced to MS People?

Thanks in advance for help.