RBRE960 reboots itself daily

MeshedUp 

The Hitron EN2251 is a Puma chipset based modem.   Anything Puma based is notoriously problematic.

I see that this is a voice support modem as well -   are you getting voice (telephone) service through this device as well as internet?  If so, the next time you see the Orbi drop - pick up the handset on your telephone and see if you have a dial tone.

I had a Hitron based modem from Spectrum - and had similar dropouts - always with a loss of telephone service at the same time.  While lights on the modem never changed - all services provided by it were lost including both internet and voice.   Spectrum always reported no issues.

If you see this consistently happening, you may want to swap out with a different modem - preferably a different manufacturer.   I changed from a Hitron (Ubit made) to a Hitron (Technicolor made) and have not had a single outage since (and that was in January or February).

You may also want to monitor the Connection Statistics page  (http://192.168.1.1/RST_statistics.htm)   and monitor uptime on the system and uptime on the WAN interface.   This will tell whether the router is truly rebooting  (System Up-time)  or if the WAN Connection (Up-Time on the WAN) is dropping.