touch ID won't recognize my fingerprint

I recently purchased an iPhone 6s through AT&T back in march of this year. As soon as i got the phone i updated to iOS 9.3. my problem is touch id sometimes won't recognize my fingerprint. If I try 10 times, it usually will work 9 you of 10 times, but when it won't work, it prompts me to enter my passcode to enable touch ID, then ill put my phone to sleep and try Touch ID again, but it won't recognize my print, any suggestions on how to fix? I've made sure the button is clean when i try iy but it sometimes is unresponsive.