This is how I got mine to work:
It appears my (Cogeco) modem puts out both 2.4G and 5G. If I connect my Sanyo Roku TV to the 2.4G network, it works fine for all functions except I cannot cast my Microsoft Surface Go to it. However, if I connect the TV to 5G, it works fine! Maybe the Roku TV is picky as to the incoming signal?
I should note that I had to go into the modem settings and rename the 2.4G and 5G outputs to different names in order for them to show up separately when I searched for them on the wifi network from the TV.
This may not be the problem with yours, but I thought i'd pass it on since it worked for me.
Did this ever get resolved? I am experiencing the same issue. I can see it on my work computer which also has Windows 10, so I know the Roku Ultra is working fine. However, it never is found in Action Center>Connect. Like MysticalFists said,it can be discovered and installed in Printers and Devices, but it makes no difference for discover-ability in connections.
Are you running Windows 8.x or 10? If yes then I would recommend following the advice that was provided before, which is, to disable the Windows firewall that the operating system comes with as a testing mechanism. If this work while being connected to your internet's provider network and also your home private network then this means that you need a firewall rule configured to allow both networks to talk to each other.
My case, was a little different in relationship to the networks. It was my private home network and the private network that Miracast uses for display.
Because I've been dealing with this forever and finally got out of it today, here's what the issue was for me.
Can't connect Windows 10 system to TCL Roku Tv (device would show up when using action center - connect, then it would just say "Can't connect."
Works from android phone just fine. Works from another Windows 10 laptop just fine. Ruled out router, wifi, factory resetting TV, tons of changes (try default, try permissive, etc. etc.)
What ended up working for me finally was when I compared my wireless adapters from the two systems (which are very different of course) but I found a setting called "roaming aggressiveness" in the advanced tab of the adapter setting.
On my system that wasn't working it was set to disable, on the one that works, it was set to 3 "Medium." I figured **bleep** it couldn't hurt, so I changed it on my other system to "Medium" and voila, it works on both this TCL Roku TV and my Roku Ultra system.
Just thought I'd drop this out there for anyone else who has hit a wall forever. My systems have Miracast support and all that stuff but this was a pure rabbit hole from **bleep** that I got lucky and found one setting that was blocking me out for whatever reason....
Resetting the network forgets the network password--even if this works, it would be too much work to switch back and forth between showing the computer desktop and showing Roku channels!
This is the only post where I saw something about resetting the network connection. I tried several of the other complicated suggested solutions, but nothing worked. Finally I simply tried resetting my network connection, and it worked! So thankful! I have a Sharp Roku TV.
i am having the same problem
This deep into the thread, you need to be more specific, please. What exactly isn't working, what model Roku, what sort of computer?