Cannot launch appium inspector- XCTRunner - assertion failed: and Enqueue Failure: UI Testing Failure - App accessibility isn't loaded [SOLVED]

Appium version - 1.6.3
Desktop OS/version used to run Appium: Mac sierra 10.12
Node.js version (unless using Appium.app|exe): v6.9.5
Mobile platform/version under test: Xcode 8.2.1
Real device or emulator/simulator: iPhone 7

Cannot launch appium inspector. It worked fine before. But now open app and close. Appium popup says “Could not start a new session.”

 [XCUITest] Unable to start WebDriverAgent session: An unknown server-side error occurred while  processing the command. Original error: Failed to launch com.4axis.EngineExample application
[debug] [XCUITest] Quitting and uninstalling WebDriverAgent, then retrying

link to appium log

Use new appium desktop version.