I was also facing this issue.
I think, Appium v2.0.0 or onwards are not compatibale.
So, when I installed v1.22.3 of Appium and tried again it started running properly.
Hope you try once and this issue will be resolved as resolved at my side.
Appium v1.22.3: npm install -g appium@1.22.3
Happy Testing!
Thank You.