iPhone looses connection to iTunes

I am trying to sync via USB between an iPhone 8 running iOS 11.2.1 and a Mac running High Sierra 10.13.1 with iTunes 12.

The sync gets to calendars and then drops connection with the error:

"The iPhone "phone name" could not be synced because the connection to the iPhone was lost."

I have restarted the iPhone several times and am active on the iPhone to make sure there is not a time out. At no time did I unplug or wiggle the USB cable. Yet my sync continues to fail.