Diagnosis
Solid orange Internet light means the Orbi router is not getting a valid IP address from your modem. This is a WAN/ISP handoff problem.
How to Fix It
Power cycle the chain: unplug modem, unplug router. Wait 2 full minutes. Plug modem back in, wait for ALL its lights to be solid (not blinking). Then plug the router back in. Wait up to 5 minutes for it to negotiate and turn white.
If That Didn't Work
Log into your modem's interface directly (if possible) and check if it's in bridge mode. If not, you may need to put it in bridge mode or, if that's not possible, put the Orbi in AP mode (which disables some features). Alternatively, a faulty Ethernet cable between modem and router can cause this.
Heads Up
Some ISPs lock the IP address to the first device connected after a reboot. The modem MUST be fully online before the router is powered on, every time.