internet connection problem in ca (help needed)

all right, i got a modem, and a router. ever since i updated my router's firmware, i been getting the error in ca everytime in the middle of game and client closes.

i tried turning off my router and only modem on, ca works but i wanna know how to make it work with my router and modem on.. it used to work but ever since i updated my firmware for router its been getting that error...

if you know how to fix it, please say.. btw if i need to, should i contact nexon for this or my router provider (belkins)?

ummm isnt a router and a modem two different internet connection like that gives u internet but idk u probaly just have to pay without a router then if your internet still works without router then your good but it doesnt that suks