Problem

I was running React Native on iOS and got the error:

error Failed to launch the app on simulator, An error was encountered processing the command (domain=com.apple.CoreSimulator.SimError, code=405):
Unable to lookup in current state: Shutdown

Solution

Open settings:

•  > System Settings…

Go to storage:

• General > Storage

Click on the developer icon:

• Developer ⓘ

Select the build files:

• Xcode Caches
• Project Build Data and Indexes

Delete Xcode cache:

• Delete…

Rerun React Native and open the Simulator device:

npx react-native run-ios