About "router mode" and "NAT mode" in the router connected to optical fiber"

The "vro mode" and "NAT mode" in the router connected to the optical fiber have been working for a long time today, which wastes a lot of time and is stuck in the working mode of the WAN interface of the router. WAN: optical fiber, static IP address. There are two ways for a vro to work: "vro mode" and "NAT mode". I tried to use "vro mode" without thinking about it. The result is that I have never been able to access the Internet, use "NAT mode. Another note: At first, I tried to change the vro mode to the NAT mode, but I still couldn't get it up. Later, the vro hard reset. After the factory settings are restored, I can work in the NAT mode.