I don’t know why, but mine keeps doing the same thing. I have unplugged it multiple times to restore the connection, only to have it drop in and out a day or two later. I’m about ready to try another brand, or actually pay Spectrum their rental fee so they can take responsibility for it all.

Since you are experiencing intermittent internet connection, please let us know whether it's through wired or wireless connection.

If it is a wireless connection, I would suggest changing the Wi-Fi channels and monitoring the performance for 24 hours.

http://arris.force.com/consumers/articles/General_FAQs/SBG8300-Changing-the-Wi-Fi-Channel

If it is with both wired and wireless connection, I request to check the cable signals.

http://arris.force.com/consumers/articles/General_FAQs/SBG8300-Cable-Signal-Levels

Another thread started not too long ago by oSam9 since he and I are also having the same issue. The signal strength is good, changing from wifi the ethernet or changing ethernet does nothing and the service provider confirmed there were no issues on their end. This is not a function of connectivity but an issue within the modem/gateway

I’m having the same issue - started a few months ago.  Modem disconnects /reconnects multiple times.  Service provider came out and confirmed no issues on their end.  It’s obviously within the modem.