The 104 error code means Core Motion Activity is not available on the current device. I was seeing this on the simulator only, but did not see the error when I built to device. The sim does not have CoreMotion hardware capable to give the Core motion data.
References:CMErrorMotionActivityNotAvailable.rawValue is 104 which explains the original error CMErrorDomain Code=104
CMErrorMotionActivityNotAvailable documentation can be found in the Apple developer documentation (Apple doesn't let me post the url here)
CMError can can be found in the Apple developer documentation (Apple doesn't let me post the url here)