having problem with my lockscreen I have tried everything,
Knox is on,
Android device manager is on and its still not working.
Your question was already answered here:

Try this:

Open your Settings.

Scroll down and select Security.

Clear Credentials.

Check the Screen Lock setting to see if the low-security options are now enabled.


If that doesn't work, you can revert your lockscreen security to Slide.

Set your lockscreen security to Pattern from Settings&gt;Security&gt;Screen Lock.

Click the power button on your phone to lock it.

Click the power button again, but don't unlock your phone. There should be a button labelled Forgot Passowrd. Note: On some devices, you may need to incorrectly enter the password/pattern several times until that option appears.

Enter your Google account credentials.

Your lock settings should now be Slide.


Note: With this method, the option for Slide security will still by disabled, but you should still have it as the lockscreen security on your phone.