LGG3 Account Unlock Not Working

[AC Question]

My phone has locked itself while being in my pocket. It is now asking me to enter in the backup pin or sign in with my Google account but for some reason it isn't accepting my Google account and I can't remember what the backup pin is(I've tried everything). Any reason why my device is refusing my Google login even though the email and password are correct? I am able to access my Google account perfectly fine on my PC.