Your switch should connected after the router.
Modem ----> Router ----> Switch ----> Devices
Another case of trying to pull multiple public IP's?
If the TWC device is an advanced gateway (all in one) and it's in NAT mode, you will create all sorts of issues as well.
If you need to configure it with multiple devices you must make sure the gateway and DHCP starts are on a different subnet .
Otherwise, get rid of the switch, call twc, have them put their device in bridged mode and turn off it's wireless radioss, connect your router to it's first port and then your switch to one of your routers outputs.
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