Why my blu cell phone does not ring for some incimng calls but does for some other incoming calls?

[AC Question]

My blu cell phone has sound for everything else that I set up for, but it does not ring for some incoming calls, but it does ring for some other incoming calls.

 

[B. Diddy]

Welcome to Android Central! Is it the same contacts that don't ring each time? If so, open your Contacts app, select that contact, tap the Edit button, then Menu, and make sure you haven't set an invalid ringtone for it.