Diagnosis
The router has lost its connection to Netgear's cloud servers, but your local network and internet are still functioning. This is a common cloud sync/account issue.
How to Fix It
Log out of the Orbi app completely, force-close it, then log back in. If that doesn't clear it, reboot the router by unplugging it for 30 seconds. The ring should go blue/white once it's fully back online.
If That Didn't Work
Check if your ISP's modem/router has changed its IP address or if you have a double NAT scenario. Log into the Orbi web interface (orbilogin.com) and check the Internet status. You may need to release/renew the WAN IP.
Heads Up
An amber ring only means the cloud connection is down, not your Wi-Fi. If everything works, you can often ignore it temporarily, but it will disable remote app management.