My Iphone 6 screen goes black every time I make a call, and is unresponsive until I do a hard reset? Help!

I think there might be a problem with the sensor inside it. If that's the case then you have to bring it in and they will fix it for free.

No idea. But I doubt it's anything you did. It's probably a faulty sensor.

Mine does the same thing, since new, updates have not fixed, would guess a bad sensor.. screen goes black, can still talk/hear, can't do anything until other person hangs up and phone regains function shortly after call is ended, or have to do a two button reset to get it to work again.

Apple replaced with new phone under warranty, had to haggle a little to get that done. Set up new one as a new phone, not from a backup, so as to not transfer any possible software issues to the new one, still re-setting up everything... all was good for the first week or so, now this one does the same thing, plus a new issue. While on calls the screen will go black, and the absolute only way to get control of the phone again is to hold both buttons down until the apple logo appears and phone restarts. Additionally, sometimes it will now become unanswerable when receiving a phone call, has only happened on vibrate, but it will go into a continuous vibrating mode and no way to answer the call or stop it, other than the two button restart. Does it on normal calling, and on 4g lte calling setting (verizon).

Same happens to my phone - screen goes black and can't be brought back without a 2-button reset. Actually on mine, the problem seems to get worse and happens all the time now