Appium error

SessionNotCreatedError: A new session could not be created

Appium rejected the session request. It's almost always a capabilities mismatch against what's actually available on the device/emulator.

Why this happens

`platformVersion` or `deviceName` doesn't match any connected/available device exactly
The driver (UiAutomator2, XCUITest) version doesn't support the target OS version
`app` points to a path or bundle ID that doesn't exist on this machine

How to fix it

Run `appium-doctor` to verify Node, Android SDK/Xcode, and driver versions are all compatible
Copy `deviceName`/`platformVersion` exactly from `adb devices` / `xcrun simctl list` rather than guessing
Confirm the `app` capability path is valid and reachable from the machine running the Appium server