VNC Service Start Error -ZTE Z5S Mini Works-

[bejo]

I have tried porting Nethunter for my smartphone as follows :
ZTE Smartphone Z5S Mini
PNY OTG
Wifi USB Buffalo WLI-UC-GNM, Chip: Ralink RT8070 (rt2800usb)

and all goes well Wifite successfully executed, but for my VNC can not perform the service call, I've set up the 8 char password. The following display Error VNC Start Service.
" vncserver : the USER environment variable is not set.
Display Number :X will be port 590X
Please any key to continue..."

any advice for VNC fix the problem?

see attachment picture.

thanks