I’ve seen this a few times and it’s always surprised me until I’ve figured it out. Hopefully this brief post helps someone else one day.
Years ago a friend of mine had me over to help take his phone apart. The headphone jack had stopped being reliable (yeah, way back in the day when it was normal for you to plug in headphones). We had fun taking the phone apart, but in the end it turned out that the headphone jack was jammed full of pocket lint. Yup. Some careful digging with a pin and tweezers and we cleared out an alarming amount of lint that had jammed up the port. This fully restored the headphone jack function.
One of my kids had the same thing happen to them. Janky headphone jack, and yup – the bottom was stuffed full with pocket lint. Just be very careful poking around in the port. It’s not very big and you can mess stuff up. Lint is soft and will come out with some gently coaxing.
Lately my ~1.5yr old Pixel 4a had stopped reliably charging. The USB-C cable would fit in fine, but not stay put. It would also pop out very easily. This morning after another failed to charge overnight incident I again inspected the USB-C port. It looked fine. Probing very gently with a pin, it soon became obvious there was some lint in there. Then I pulled out more and more.. an alarming amount. There was a lot of lint. Now I can look into the port and see the shiny plastic bottom, not a dark matted blackness. The USB-C cable seats nice and deeply and doesn’t pop out easily.
Given phones probably live a good percentage of their lives in your pocket, this isn’t a surprising outcome. Still – cleaning out lint wasn’t even close to the first thing I thought of doing in any of these cases. I’d even checked what my warranty and repair options were. The fix was 2 minutes of careful work.