Local testing has not been connected through BrowserStack
BrowserStack enables you to run automated tests on your apps against your internal development environments or environments behind a corporate firewall. This feature is called “Local Testing”.
You need to Download and Run the BrowserStackLocal binary.
Set-Up the Local Testing for Mobile Apps using Appium
Remember to set the browserstack.local capability to true in your tests.
"browserstack.local" : "true"