I have a Spectre android TV and I’ve had it for about a year but the remote broke after about a month so I started using the android TV app were you put in a code on your phone that shows up on the tv and you get a remote screen and all of a sudden a few days ago it stopped working and it says make sure both devices are connected to the same Wi-Fi even though The TV and my phone are connected to the same Wi-Fi
Google updated the remote receiver app for AndroidTV to connect using the updated GoogleTV app for your phone, only way to use old Remote app is to disable Auto-Updates from Play Store and "Uninstall Updates" to the Android system Remote app in TV.
Search this reddit, the News stories were shared that the change was coming months ago and dozens of comments about it working and not working usually because the TV or the Phone app hadn't yet been updated.
Recommend you getting a universal remote for your TV, got myself a nice GE remote with button backlighting for less then $10 from Amazon.