How to disable screen lock on Huawei P8 lite? I cannot remove the lock screen on my P8 lite.

I go to Settings &gt; Screen Lock &amp; Passwords &gt; Password.  There, I can only choose Pattern, PIN or Password, but I cannot tap on None.  Under that, is this: Disabled by administrator, encryption policy or credential storage.

What does it mean, and what should I do?
I have same problem and nothing worked, including clear credentials. Only thing that I didn't try is set pattern lock + extra PIN and then provide wrong pattern 5 time. On other topic they say that is working. Here is the link.