ARKitImageRecognition

I'm trying to run the sample code provided by Apple. I'm getting:

/Users/me/Library/Developer/Xcode/DerivedData/ARKitImageRecognition-dbzdmsowoqmsaqejorbxkompvdfl/Build/Products/Debug-iphoneos/ARKitImageRecognition.app/Frameworks/libswiftARKit.dylib: unknown error -1=ffffffffffffffff
error: Task failed with exit 1 signal 0 {
  /usr/bin/codesign '--force' '--sign' '02832D01E3EA1AF5F65ED0EB4934262B31E2FDDB' '--verbose' '/Users/me/Library/Developer/Xcode/DerivedData/ARKitImageRecognition-dbzdmsowoqmsaqejorbxkompvdfl/Build/Products/Debug-iphoneos/ARKitImageRecognition.app/Frameworks/libswiftARKit.dylib'


I thought it might be DerivedData, but I've dumped that. Tried restarting. This error persists. Help?