My Jlab Audio Earbuds work fine with my 2014 iMac, 2015 Macbook Air, Nintendo Switch, 3DS, and PC. They used to work with my iPhone 6S, but have stopped functioning recently—I can technically get them to work if I jiggle the cable and stay very still, but the audio cuts out as soon as I move.
Given that these headphones work fine with other devices, I would normally surmise that there's something wrong with my iPhone. However, I've tested two other pairs of headphones with my iPhone, and they all seem to work fine.
This exact problem happened once before, around nine months ago, and buying a new pair of headphones fixed the problem. Now that the issue has reappeared, I'm wondering whether I should just replace the headphones yet again, or get my iPhone looked at.
More generally, I'd like to know what the heck is going on. How can this be, and which device is responsible?
All above references to "headphones" refer to devices that connect via the 3.55mm audio jack, and not Lightning or Bluetooth.