Touch ID will not unlock the iPhone.

Hi everybody. Touch ID on my iPhone quit working when unlocking the iPhone almost alltogether. It worked perfectly for 9 months or so, but suddenly the Touch ID quit unlocking the iPhone. Maybe 14 out of 15 unlockings used to work like a charm, but now barely 1 out of 15 works. I havent had any problems when making purchases with Touch ID.

Anyone else having the same issue?

Solution to the problem would also be nice!