I have the same problem! Press volume+ and power simultaneoulsy doesnt work :(
To force a shutdown/reboot press Vol Down + Power. To enter maintenance mode press Vol Up + Power ( + Bixby if one exists ) AT START. When the phone is up and running Power + Vol Up won't work.
Thank you for the help. Unfortunately this does not work. I am asked to enter a password, but I have never set a password. I also cannot create a new security code or password, or a fingerprint or face recognition.
I am also facing same issue on my s8+, showing incorrect pin, from last 2 years i am using same pin..
I re-entered the pin more than 14 times and the phone is reseted to factory default..without any data..