What's the firmware version? Provide the topology pls. Except the camera, all other clients in your network are working properly?

it shows screenshots of the MR3040 in use with Greenpacket UH350 modem after firmware upgrade. What kinds of firmware? Is it a third party one? Did you try the latest TP-LINK firmware?

Not sure. You may have a test in the shop before you buy the router?

Hard reset it and check IP address obtained on the PC connected to MR3220.

Have you tried different web browsers or different computers? Before upgrade, did you extract the firwmare file and connect PC and W9980 by cable?

My page loads very slow sometimes and I unable to logon the router UI 192.168.1.1 If you cannot logon the router, how did you check the system log? When it happens, how about status of all lights on...