S5 Neo incorrect pin message

[Red Dwarf]

Left my phone on charge overnight. This morning I cannot get in as i am getting an incorrect pin message.
I have been using the same pin for a couple of years. No one had access to my phone.

 

[B. Diddy]

Welcome to Android Central! See what happens if you boot into Safe Mode: https://support.t-mobile.com/docs/DOC-28456