: Android 5.1.1 utilizes an outdated Application Programming Interface (API 22). Modern streaming platforms require newer protocols to ensure media decryption and security.
Go to Settings > Apps > YouTube and select "Clear Cache" and "Clear Data." youtube for android 511 top
This is the easiest method to safely sign in to your Google Account on Android 5.1.1. You will gain instant access to your customized subscriptions, watch history, and library. : Android 5