Most likely you do not have OEM unlocking enabled in the debugging options of your phone which means you may have to do a factory reset.
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Most likely you do not have OEM unlocking enabled (needed to flash files in fastboot mode) in the debugging options of your phone which means you may have to do a factory reset.
I wonder is it possible to install custom recovery like TWRP on this?
If yes, then the screen lock should be removable.
If you can boot TWRP without wiping the phone you can use the file manager on there with system partition mounted then navigate to:
"/data/system/"
Delete or move to another folder:
- locksettings.db, locksettings.db-shm and locksettings.db-wal
Once this is one, reboot phone from recovery and the phone should have no lock screen.
I have only tested this on android 6.0.1 to 7.0 Samsung Firmware.