Check out the steps to make your AOL app work again if you're unable to sign into AOL mail on Android device. If you receive an error message, try signing in or adding an account in the AOL app. It is best to force stop and restart the app.
Open the Settings app.
Click on the apps.
Then click AOL.
Press the stop button to force the stop.
If asked, select force stop again to confirm.
As a last step, relaunch the app and see if you can reproduce the problem.