CODA56 modem randomly dropping internet connection

I have a new Hitron CODA56 modem on Xfinity cable internet - which was working for the last 4 weeks or so but in the last week has started random disconnecting. It seems to happen particularly when I am on Facetime or Zoom. This happens even when I connect directly to the modem via Ethernet cable to my computer. The modem shows normal blue and green lights throughout the episode, which lasts about 10 minutes. 

Is there someway to troubleshoot this?