Tony Seaford wrote

192.168.200.250 is a private IP... It cannot be accessed remotely.
On the modem, open port 80(you'd better use a different port like 81) for the router to remotely access it with http://modem's WAN IP:port.

I try to change port to 8080, but still not work. I am not remote from outside i just remote in local VLAN. For other brand Router I can remote from WAN IP.

I have 4 VLAN
VLAN 1: for local office use IP rang 192.168.136.xxx
VLAN 2: for local wifi use IP rang 192.168.200.xxx
VLAN 3: for local server IP rang 192.168.17.xxx
VLAN 4: for local VIP office use rang 192.168.0.xxx

each VLAN can ping to each other and I want to monitor all WIFI router in VLAN 2 from VLAN 1. I can remote for other brand of router, but for TP-Link cannot.
Have you any solution or firmware to solve this problem?