Error when trying to start session with appium “unknown server error” Code 255

Question

I need an answer cause I searched a lot and I didn't get anything

I got that error when I tried to start the server normally

I just wrote that on desired capabilities

{
  "automationName": "Appium",
  "platformName": "Android",
  "platformVersion": "9",
  "app": "C:\\Users\\lenovo\\Downloads\\eribank.apk",
  "udid": "3ce85865",
}

What should I do more? Or what is the problem from the beginning?

Android_Home checked and path too.

Answer 1

This error is because Appium will try to install some apps like 'Appium Settings' in your test device. To install the app, Appium needs the 'WRITE' permission. This is the reason for error 255.

Possible troubleshooting:

1. Check if you have enabled 'Developer Options' in your device
2. Check if you have enabled 'USB Debugging' toggle in Developer Options

Answer 2

Add to above Developer option and USB Debugging enable. You will need to allow "install via USB" in order to make it success.

Be ready to response to any prompt on your mobile. (No need for Emulator based)