“Logged in fine yesterday, today it says ‘Action required — update Google Play services’ — but Play Services 23+ no longer supports Lollipop.”
You need Google Play Services 21.xx or lower. Update your Play Services via APKMirror (search for “Google Play Services for Android 5.1”). Restart your phone. app youtube android 511 verified
: Older devices often have expired security certificates, making it hard for the app to connect to Google's servers. Third-Party Alternatives “Logged in fine yesterday, today it says ‘Action