Hello, fellow sufferers.
I have had the same problem since upgrading to iOS10. This issue occurs on my iPhone 6S Plus (on O2, bought from Apple online), my wife's iPhone 6S Plus (on Vodafone, bought from Apple store) and my son's iPhone 6 (bought from Vodafone store). All 3 were bought from different places at different times.
On my phone, I have tried:
- Factory reset then restore
- Factory reset and set up as new phone
- Upgrading to the 10.3 beta
- Swapping out my headphones
- All the suggestions here and more
Nothing works. The only temporary fix is either to reboot or switch to speaker and back, and even then, these "fixes" only work for a short while (I use my phone all day for my work).
I phoned Apple about this on 3 occasions. Each time they try to palm me off with a replacement phone. Note: having had a replacement iPad, you should bear in mind you do NOT get a new phone if Apple swap you out, but a refurb. I told them I don't want/need a "new" phone - it is not a hardware issue. I tried to get them to let me email them this thread so they can see it's a widespread issue but they refused that. I asked them to admit there was a fault with iOS; they would not. Just kept saying over and over "let an engineer look at it and we can go from there".
I am convinced this is poor programming in iOS10 for that stupid iPhone 7 headphone jack. I'd go back to iOS9 but my backups from then have been overwritten.
Frankly, considering how overpriced this Apple piece of junk is, we should receive better service. At least admit there's a problem! This is taking the p*** now.