Diagnostic Software for iPad fingerprint button?
Beta software is not considered stable. The first troubleshooting step should have been removing the beta software. If this did not resolve, completely wiping the device using iTunes > Set up as new (not restored from a backup). If the button does not work after a full wipe and set up as new, it could be indicative of a mechanical failure. Apple can run a diagnotic over the phone or in store to see if the Touch ID module can be detected. More likely the beta software.