Have you tried rebooting your home network and the device, then trying to set it up again? I'd also recommend connecting the device to a different wireless network, such as a mobile hotspot, and seeing if you experience the same result. There could be an issue with your network's configuration that may somehow be causing an issue, but it's hard to say.
After struggling thru numerous factory resets, it got to the point where I couldn't get a reset / re-install to complete.
I gave up and, for lack of a better idea, purchased an Express +. It worked... until this week, when the new Roku decided it had no internet connection. When the connection was configured, it said it had internet, If you go immediately to 'check connection' it said the wifi connection was excellent, but there was NO internet.
Same process.... factory resets, re-installs, until, while searching for solutions, I found something on the internet about DNS servers. So I started playing with my routers DNS configuration.
When I switched the primary DNS from google (8.8.88) to Cloudflare (220.127.116.11) my new Roku started working!
I then hooked up the old Express, which couldn't complete a configuration, and it worked!
Doesn't make any sense to me, but it's working now.
Is there a fix for this? My new express downloads the update and then goes into reboot loop until it times out back the select your language screen. The network is working fine for all other devices, has been rebooted. I've tried several cables, HDMI ports and dozens of factory resets on the ROKU. My roku stick works just fine on the same network, and TV.