Sometimes iPhone gets stuck in Headphones mode preventing you from hearing the sound. The problem is that iPhone mistakenly acts as if headphones are plugged in.
Unplug your Headphones
If you see the icon below when you adjust the volume buttons, there may be debris in the headset port. To remove, unplug then re-plug headphones several times (at least 7-8 times).
Some users have reported that they fixed this problem successfully by using a hair dryer or sucking (hard) on the headphone port. You may also want to use a toothpick or a Q-Tip and clean the port to remove any remaining dirt / particles. Always make sure you turn your phone off before taking any of the steps listed above.
Blow into the headphone jack
Before you actually use a compressed air machine or canned air to blow it into your iPhone’s headphone jack, get a flashlight and see if there is anything stuck inside. If something is noticeable, take it out. Now, carefully and gently blow air right into the headphone’s jack. That should remove any small particles.
Use (or Make) a Tool
Some users find that an interdental brush helps to clean out any dirt and dust from the headphone jack. You can find an interdental brush in almost any grocery store or drug store. You clean with a light touch, just brushing the insides of the headphone jack. You can also add a bit of rubbing alcohol to the brush to help remove anything that might be stuck stubbornly on. Remember to use just a little bit and make sure your phone is off before inserting any tool into the headphone jack.
Another method is to make your own very small lint brush by using a paperclip and some transparent tape. Bend the paperclip straight and wrap the paperclip’s tip with the transparent tape, sticky side facing outwards. Make sure the tape is tightly wrapped around the paperclip. Gently insert the sticky tip into the headphone jack, lightly pressing it side to side to pick up whatever dust and dirt is there. Remember to turn off your phone before you try this and always use the lightest of touch.
Reset your iPhone
Some users found it helpful to turn off their iOS device and then turn it back On. If those solutions doesn’t work out for you, this method might actually help. Give it a try and let us know what’s going on. If you are still having this problem, contact Apple support.