How to enable lock screen password in BlueStacks 5 on Android 7.0 Nougat?

I installed Bluestacks 5 recently. It is also rooted. I want to install a CA certificate on the device which is Android 7.0. To install the certificate, I have to set the screen lock first. But when I check the Settings, I can't find any lock screen password. I did manage to access the password setting somehow but it automatically set to None. So I am not able to set any password in it. Please help me to set a password.