Hi, I've had an iphone 6 since early December. In early February I got a replacement iPhone due to a faulty sleep button. In all the time I had the first iphone 6, touch id worked flawlessly. But with this phone it fails very very often. I'm not sure what is wrong. I made sure hte sensor was very clean using glass wipes but still fails often. Do you guys have any tricks or issues similar to mine? thanks.