Your problem may have been caused by an update to your router which affects some Roku models. If you receive this update it changes the router's wifi connection parameters for the 2.4 GHz wifi band from b/g/n to g/n. This has been reported for routers supplied by Comcast/Xfinity, Cox, and AT&T, but there may be others.
Affected users report the Roku identifies the local network as available and rates the connection quality, but will not then connect. The fix is to switch the router configuration protocols from the g/n wifi set by the update back to b/g/n. If you don't have access to your router's configuration controls you may have to have your internet provider do it for you.
Step-by-step post from AvsGunnar for Comcast/Xfinity users:
https://community.roku.com/t5/Network-Wireless-Wired-Connections/Error-014-30-stuck-for-three-days/m-p/749194/highlight/true#M21388
It's not actually my router, it's a public xfinitywifi network that somebody else is broadcasting, presumably from their Comcast-provided router. It was working fine yesterday but then I switched accounts (yesterday, but I guess it kept working for another day) and now it no longer works. For whatever reason when it shows the Hotel and Dorm Connect screen it goes away in about 5 seconds. Not sure why it thinks it has Internet when it doesn't.
QueueUnderflow So are you in a hotel? Dorm? Are you a current xFinity internet subscriber? So you’re trying to connect to an Xfinity hotspot which is designated for Xfinity customers only correct? Why aren’t you using your WiFi?
Ello2022 I'm at home and a Comcast customer but I like to use the public xfinitywifi network insetad of my own network because it doesn't count against my data cap. As I understand it "Hotel and Dorm Connect" really just means you have to open a browser to finish connecting to the Internet.
