When my Surface Pro4 startsup - the PIN is accepted, but then the error 0x8028008b says there is a problem with the PIN and it needs to be setup again - and it gives other ways of logging-in, so I use my MS a/c password.

When I am in, and set the computer to sleep, I can use the PIN. The behaviour is sporadic - the PIN sometimes working - and other times the error.

Windows 10.