mac book pro headphones not working even with the correct sound settings .
To diagnose the problem verify the following things:


Are you sure that the headset is set as source under Input? (Make sure it isn't using the built-in mic of the computer)
If you unplug the headphones, can the MacBook play sound through the built-in speakers?
If you plug your headphones into some other device (i.e. another computer or, an iPhone), can you play sound and hear it?
With the same settings as in your screenshot but with a different headset or a set of speakers (if you have any of those), can you hear sound through the MacBook?


If the MacBook either doesn't play sound regardless of the output device, you probably have a hardware problem. To be extra sure, try running Apple Hardware Test (AHT).

If the headset can't output sound when connected to other devices, that might be what's defective.