Issues with using Two Factor Authentication Apps
I had setup Google Authenticator App with my yahoo mail accounts for two factor authentication. Once I setup the Authenticator app I had sync issues with my two yahoo mail accounts. One in particular would constantly require me to log back in. Moreover I would not see updates to my mail unless I toggled between the two accounts through account manager function. That only worked on a web browser. That function wasn't possible with the Yahoo mail app.
Could you please message us on Twitter at @YahooCare or on Facebook at Yahoo Customer Care? We'd like to look more into the issue you're experiencing. In case you do not have a social media account, we are also available at: help.yahoo.com
Looking forward to your reply!
Yahoo Mail team
Richard Jones commented
So I don't use Twitter and never will. You don't have your own customer center vs going through Twitter or FB?
The problem still persists and mail delivery to one of my Yahoo accounts just doesn't seem to happen via app at all. And the sync function that allowed me to login and view both my Yahoo email addresses seems to be completely broken on web browsers.