getting my gateway back online after moving my gateway from downstairs to upstairs

I moved my gateway, wifi extender and modem upstairs to my room from the basement. The xfinity app says my gateway is offline but the wifi extender is online. I only have half the things I use online that work. I have 2 computers with 1 of them working sometimes and the other will not load the work my Mother needs to do. The TV's do not work long enough to even watch tv at all.