- Check /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/DeviceSupport/ for directory name 15.4 (your iOS version).
- If the directory is missing download support files for 15.4 (your iOS version) from https://github.com/filsv/iPhoneOSDeviceSupport and place it in the above path.
- Restart Xcode.