All Acer laptops have these problems because they use very cheap (bullshit) chips in their motherboards, particularly, Realtek audio chips mounted on it. Speakers will work but when you connect headphones to the jack, it will not send any output to headphones. I googled for hours and finally got this information. Two solutions: first one is to standby your laptop for 30 minutes and wake it up (don't use restart option): it may work sometimes, if not, second one is to cool your laptop put in a freezer for 1 hour and take it out and check, it sometimes works. Anyways, I decided to goddamn my existing Acer aspire 5572awxmi laptop and would buy a new Dell laptop.