Problems with the USB testing feature


I got a little problem with the USB testing feature.
When i am home i always use the live feature with wifi, but when i am in the train its not possible.
so i tried it out but i can’t find a way to make it work…

i downloaded the MakeroidStarter and i plugged my phone (Galaxy S8 “samsung”) in my laptop.
every time i try it, i get this warning.

Can someone pleas help me??

Is usb debugging enabled in your device???
Also check that you have enabled file sharing bcz somethimes your phone connect and only get charge