Android device manager won't reset the password So, here is the problem.
My girlfriend changed her numerical passcode on her Samsung Galaxy S2 and she forgot the password. She had installed Android device manager before on her device but I still cannot reset the password. After reading some advices and forums I realised that you need to PERMIT ANDROID DEVICE MANAGER TO START WORKING ON THE DEVICE ITSELF.

So, is there a way to confirm that permission remotely? Otherwise, Android device manager is useless for things like that.

Thank you, Regards
No, you can only activate Device Manager on the device itself. This is for security reasons. The idea is that you activate it before losing your phone or forgetting the password.

Normally you don't need Device Manager to deal with a forgotten screen lock pattern, PIN, or password. After entering it wrong several times (usually five), the lock screen should offer you the opportunity to log in with the primary Google account attached to the device, or to factory-reset it. That might not work if you have a device administrator installed, such as a corporate email account or VPN credentials.