X1 4K HDCP Error

XG1v4 DVR.  This has now happened three times in the last week or so.  I try to go to one of the 4K channels (1354-57, 1390-91) and get an error message saying there's an HDCP error.  Restarting the X1 box clears the error.  This is a box I've been using error-free for 4K for a couple of years.  I watched the World Series game in 4K last night, then I had to restart the box again this morning.