Appium Request to register with grid was unsuccessful: Error: getaddrinfo ENOTFOUND http http:80 while starting Selenium Grid Node
This error message...
[Appium] Appium REST http interface listener started on 127.0.0.1:4723[Appium] Request to register with grid was unsuccessful: Error: getaddrinfo ENOTFOUND http http:80[debug] [Appium] Hub down or not responding: Error: getaddrinfo ENOTFOUND http http:80...implies that the Appium Client was unable to register with the Selenium Grid Hub
Your main issue is within the --nodeconfig for the parameter url within MKs_tablet.json where the protocol http is specified twice.
Solution
Within --nodeconfig, the parameter url within MKs_tablet.json must be set as :
"url":"http://127.0.0.1:4723/wd/hub"