Can't set default browser, how to disable the lockscreen?

Meizu M2 mini.
I can’t set up any browser to the default - it seems that stock browser is blocking everything and it is the default browser - you can’t set up any other like CM Browser or Chrome, Opera… When I try to set up CM to default browser, there is a error.
Second question is - how to disable lockscreen in Meizu M2 mini? There aren’t any settings for the lockscreen. You can’t set up anything…

Flyme OS 4.5.3O Android 5.1, original updated

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