Why has the sound stopped working on my ZTE phone?

[AC Question]

My music suddenly stopped playing but when I checked the music was still playing but the sound wasn't working. I put my headphones in and it worked then but it doesn't when I take them out. I have rebooted it many times but it seems the loudspeaker isn't working which is annoying as I can't hear if anyone's calling me or of my alarm's are going off but all the sound works when I have my headphones in