Arris SB6190 has bonded high speed upload and download connection, but... ...no internet...

...or it’s rarely available.

I’ve tried a factory reset among many other things. No matter what I do it restarts and has solid blue lights for download and upload, but no light for internet connection. Connectivity does exist a every once in a while as I’ve been able to hit a random webpage at very infrequent intervals.

I ran Comcast online diagnostics with a forced reboot and it said it was fine.

Any ideas?