Yahoo mail not working since beta update in March!

Since update in March, yahoo has not sync’d and I verified username and password, but when I click NEXT the program says I have validation error of name or password.

Veried credentials by going to yahoo web site and logged in with same info!

Problem started with update…

I believe that yahoo is now forcing the use of “app passwords”:

so you will need to set one up and use it with K-9. The password you use to log into their site will no longer work for a “3rd party email app”.

It worked on my tablet, but not on my phone. Even tried to generate a different app password but none helped. Is there a trick for K9 to be used on two units?