If the Yahoo mail has stopped responding on Android, then it might be possible that there is something wrong with your device, Yahoo server, or with the network. The answer to your question, why is Yahoo mail not working on Android, is given below:

1. A problem with your device can be the culprit. Try running other apps to be sure.
2. Unclear Cache and Cookies can interrupt the loading of the app. Clear them all from your Android to resolve the issue.
3. A weak internet signal can also be the reason. Check your router to solve your problem of my Yahoo mail is not working.