Why when i try to lock on ADM it doesnt show the password box on my phone?

[AC Question]

My mom made a new pattern for her S7 and she has forgotten it, so I read I could unlock it using Android Device Manager and so I did. I put a password and everything but then after it says " Since google has verified that a screen lock is already set, the pasword you entered wont be needed".

Please help, dont wanna lose files and photos on the phone. We have alot of memories on there