Ahh!! I have this every time my internet gets disconnected, and just figured it out. I have Xfinity internet, and you have to change the settings for the 2.4GHz WiFi to b,g,n instead of g,n. I don't know why it defaults back to the one that doesn't work. Hope this helps!
It it becomes too much of a nuisance for you, you can buy a 2nd router (even an inexpensive one), place the Xfinity router into bridge mode, and then use the 2nd router for your network.
In the above setup, the Xfinity router will act as a modem only. No matter how many disconnections you get, your 2nd router's setting will be unaffected. (You will likely get no disconnections since the Xfinity router is now in a modem only mode.)
Alternatively, you can also just buy an Xfinity compatible router and use that as your primary router and return Xfinity's router to them. The ISP will be prevented from making changes to routers not owned by/leased from them.
There are some reports that the ISPs keep resetting their customer's routers to the g/n setting. Some have even gone to the extent of preventing this mode/protocol change on some of their router models as well.
Roku Community Streaming Expert Just another Roku user... I am not a Roku employee. Insignia RokuTV, Ultra 4660, Premiere+ 3921, Express 4k+ 3941, Streambar 9102
I'd be delighted to look closely to see how we may assist you in getting started. Do you receive an error message when attempting to connect to your wireless network or when streaming a specific channel?
For troubleshooting purposes, have you tried re-connecting your Roku to a solid wireless network to see if that helps resolve the issue you are seeing? You may also try to connect to an alternate wireless network, such as another mobile phone signal typically provided and maintained by specific mobile phone (cellular) service providers, to see if you are experiencing the same issue.
With detailed information, we will be better able to assist you.
Furthermore, if the affected device is a Roku Express, please note that both devices are only compatible with wireless b/g/n networks on the 2.4 GHz spectrum. Ensure that your router broadcasts a 2.4GHz Wi-Fi network for the device to connect.
Please keep us posted and we'll continue assisting you from there.