Another way to check outside connectivity: With the 5G modem connected to pfSense, if you go to Diagnostics / Ping and select WAN2 as source address, are you able to reach (ping) outside websites? If you are able to ping websites, but the Gateway is still showing as offline (when you are using an outside monitoring IP such as 8.8.4.4), you may need to adjust the Data Payload parameter for dpinger from the default 1 to a larger value in the WAN2 gateway's advanced settings under System / Routing / Gateways. https://docs.netgate.com/pfsense/en/latest/routing/gateway-configure.html#advanced-gateway-settings Hope this helps.