My Roku for my Samsung TV will not make a wireless connection. I tried restarting the router 3x (my phone and computer all connect). I restarted the Roku, did a factory reset and it will still not connect. I tried to make my phone a hotspot, and it would not connect to that as well. I checked my Roku TV upstairs, and that connects.
You didnt mention your Roku model # and firmware version: Settings/System/About
If its an Express, its a 2.4Ghz only model - Try manually configuring (in your modem/router/gateway) the 2.4Ghz SSID for channel 1, 6, or 11, with 20Mhz bandwidth, and "B/G/N" mode (especially if XFinity is your ISP).