Razer Phone unable to Root

[eva.razer]

Dear Experts,

I had my razer phone rooted by me earlier. Recently i have uninstalled Magisk and after that i coudnt reinstall it again. I have wiped the phone several times with no luck.

I keep on receiving the following error.

Supported API: 3
E:signature verification Failed
E:error :21

Please help me .. kindly note that fastboot option is not working it only allows me to use sideload !

Any idea ?!