Why is None option in Screen Lock greyed out?

[AC Question]

Hello, I am using a Huawei Honor 6 running Android 6.0. Yesterday, I tried the Android Device Manager on my phone using the web on the browser. It worked, it let me locate my phone, rings it and locks it remotely. It also made a Password on my phone which I have to give everytime I unlock my phone. Now before this, I did not use any password. I just swipe open my phone. Now I have to give this password everytime. I worked around it by using a Pattern unlock instead. But the problem is, the None (no password) option is greyed out and it says Disabled by administrator, encryption policy or credential storage. On Device Administrators, I have ADM, which I made Inactive, and I cleared the Credentials too on my phone. But it is still greyed out. Please help.