In order to understand your issue, please response to the next questions:
1:This modem connection was working before, because the Switch is just a device in the middle to communicate the Access Points, so will just pass traffic, there are two alternative connections in Lennar homes:
Gateway (it's a modem and router at the same time)>Switch>Access Points
This guide provides more details of the set-ups:
Most common Setups for Lennar homes users
2:Are you able to see the Unleashed SSID/Wi-Fi signal?
3:Can you connect Unleashed SSID/Wi-Fi signal? And have internet connection but slow?
Technical Support Engineer | L2 TAC Wired