Beats Monster Studio headphones give a red light when powered, but do nada after
I have Beats Monster Studio S/N A508695 headphones which give a red light when powered, but do nada after. New to this so if you have any first steps, much appreciated. I’ve tried restarting resetting, etc. There’s only the one red light when switched on, no others exist. Got them used and “in operating condition”. Do I have to download an app to my iPad, iPhone?
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iPhone 7 Plus, iOS 14