Headphone jack not recognizing external playback devices?

Up until this morning the headphone jack on my Inspiron 15R 5537 was functioning normally. Now when I plug something in to the jack, the sound stops playing out of built-in speaker, but there is no pop-up and no sound comes out of the headphones. The headphones do NOT show up in Sound>>Playback, which only shows the default speakers functioning as if nothing were plugged in. The only change that occurs when headphones are plugged in is that no sound comes out of the built-in speakers.
Is this purely a hardware issue or is there anything else I can do to fix it? I ran a Dell Diagnostics test on the hardware which found nothing out of the ordinary.