Very little help. We buy a Roku. And there’s no support. No acknowledgment that they’re product has an issue. I switched my internet provider a few months ago. Working fine for the first couple months. Then my Roku devices, plural stopped recognizing the network. I’ve reset my modem, reset the router. Everything in the house connects except for Roku. Alexa, my lights, fire stick, computer, but not Roku. Options from here suck. Buy new devices? Why should I have to? They’re less than a year old! Switch internet providers again? This is such bull**bleep**!
Furthermore, if the affected device is either a Roku Express or Roku Premiere, please note that they are only compatible with wireless b/g/n networks on the 2.4 GHz spectrum. Ensure that your router is broadcasting a 2.4GHz Wi-Fi network for the device to connect to. You can check your device model by navigating to Settings > System > About.
You can also try configuring your router and use wireless channels 1, 6, or 11 which are the preferred channels in North America. Each time you change the wireless channel, you will likely need to apply/save changes before you are prompted to restart the router.