Like another user posted here, I keep hitting this on my MSI laptop (GS65 Stealth Thin 8RF) after it boots up from the battery having completely died or having been unplugged while working on upgrades/repairs inside the laptop. When it happens, NONE of the proposed "solutions" work. No "alternate sign in methods" are listed or available in any way. Clicking the "I forgot my PIN" link does nothing or simply returns me to the lock screen again. There's no way out. Yes, I know my PIN and my account password. No, I did not enter the incorrect PIN, not even once! No, I am not given any option to type in my password instead.
Microsoft, this is the most awful user experience you have EVER CREATED. You are literally locking people out of their own machines for NO LEGITIMATE REASON. A laptop losing battery power is NOT an unusual event, a security issue, or an "attempt to enter an incorrect PIN". It is a common, ordinary, everyday occurrence. You should be handling this case correctly!
I seriously hope you get SUED for wrongly locking people out of their computers during an urgent life-and-death crisis that ends up killing people. It's the least you deserve.