No sound from headphones. Internal speakers are fine. No red light.

Hello. My internal speakers are working fine. However, when I plug in my headphones, there is no sound coming from it. My mac does recognize that it's plugged in because the sound goes off (when the music is playing and I suddenly plug it in) and I can see my internal speakers change from "Built in" to "Optical Digital-out Port."

I've read a couple of discussions regarding no sound coming from their mac and checked to see if there was a red light coming out of the jack. There is none.

Please help. 😟