meizu mx4 pro no root prompt

Greets everyone,
i’m new i’m from Greece and i need your help!

I have a meizu mx4 pro with flyos 4.5.7A and i need to ocnvert it to International. To do that thou’ i need to root my device. I did that via the flyme account settings and system privileges, Mark that it was already open even after a factory reset ! The thing is that even when i leave an application on ASK or ALLOW nothing happens, i using root checker for starters and when i have it on allow root checker wont verify root access, plus when i have it on ASK i dont even get a root prompt ! What should i do ? Is my flyos geniune or something else the seller i got it from installed ?

Thanks for you patience

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