I've been having the same issue as annahbanana419.
Initially it was working fine. It was connected to the "guest" network name and password that we give to our kids and guests. They could download the app and use their phones as a remote instead of our having to look for the remote whenever it disappeared. But then our kids were changing the channel on each other, so to reduce the contention between our kids, I changed the connection from the guest wifi to our other wifi network name and password which we DON'T give out to kids and guests. I could still use my phone as a remote, but the kids could not. It still worked fine for me.
But it had been a while and the kids were getting along better, so I decided to change the connection back to the "guest" network name. Unfortunately that messed up something so I can not use my phone (or any other phone), as a remote, no matter which network name I use, even when I've tried to connect manually.
Today when I saw your reply to annahbanana419, I went through the steps as you listed--both unplugging TV as well as doing a System restart, deleting and reinstalling Roku app from my phone, making sure both are on the same wifi network.... Sadly, my phone app still cannot connect to the Roku device. The message on the "Let's connect your Roku" screen states "No devices found. Make sure your Roku device is on the same network as your mobile phone." When I attempt to connect manually, the message states "A Roku device was not found at the IP address. Please check the IP address and try again."
UPDATE: Good news! An hour after trying all the above, I decided to try using the other network name, and it worked! I don't know why it didn't work on either network before, and now it does on one of them. I'm glad it works on our other network name, but I would like the flexibility of having it on the guest network name, as I had it initially.
Thank you for this forum
