Also try turning off your phone and remove the battery for about 10 minutes then check again.

OK, play music and try to plug and unplug several times.
if sound heard form phone just leave.
otherwise get replaced the headphone socket.

1. Once you answer or place a call, tap unlock at the bottom of the screen, then press the Clear/Speaker key located between the SEND and PWR/END keys.
2. To turn it off, press the Clear/Speaker key again.
3. To end the call, press the red PWR/END key. 
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