Can you please reply so we all can see how to fix this? Dealing with the same exact issues. Everything worked fine (Roku Premiere in bedroom and living room). Had to turn off the breaker momentarily. Roku would not connect again. Have followed all directions to restart router and both Rokus, in different orders, resetting, unplugging, etc. No luck. Everything in the house connected and working fine except the 2 Roku.
Double check that your router is still broadcasting your 2.4gzh wifi radio.
If you disconnected power to router (tripping breaker), then possible that router radio is not broadcasting, or when router rebooted it is now using settings not compatible with the Premiere, namely a Wireless Channel between 1 and 11, and preferably a bandwidth of 20mhz.
Otherwise, provide a little more info if still experiencing issues.
Roku Community Streaming Expert Just another Roku user... I am not a Roku employee. Insignia RokuTV, Ultra 4660, Premiere+ 3921, Express 4k+ 3941, Streambar 9102