Ethernet switch with ARRIS TM3402

I am without WiFi short term and am trying to connect an unmanaged Ethernet switch to the ARRIS tm3402.  Is there anything special I need to do? I have rebooted everything and connected the modem to the switch, then the computer and tv to the switch.  The TV connects most of the time, but the computer does not. The computer connects if I wire it directly to modem

Phone works.

As a note, we have been having trouble with internet for a few weeks now. Not sure if it is the modem or not.  This is our third modem after two service calls.