SB6141 modem code Z00.0 - dropping internet connection

Hi,  The Arris SB6141 log shows this code 2-6 times daily corresponding to when the internet goes out (for a couple of minutes at a time).  This is a recent development.  We have a single coax cable running from the Xfinity box to the modem.  I have checked the connections on both ends and the full length of the cable (no cuts or kinks).  Is this a modem issue or an issue on the Xfinity network.  There was a post about 4 months ago with this same problem, with lots of views, but the dialog went to DM and a resolution was never publicly posted.

thank you.