Setting up new router to same Wifi settings doesn't always work.
I recently bought a new gigabit router because my old one wasn't handling network traffic well and reducing our speed to all devices within the house. I set the wifi the same so that all devices that use it wouldn't have to be reconfigured. 2.4 and 5 ghz were enabled. I immediately noticed that we began having problems. There were long delays (Disney, Acorn) or they wouldn't load at all and we had a message about connection issues. Simply setting up the wifi the same on the new router didn't seem to work. We tried setting to channel 6, turning off 5ghz, switching to b/g/n; nothing we did improved the situation.
After trying various things without success, resets etc., we decided to use our old router as a wireless access point just for the Roku.
We left all wifi settings in the old router the same except for changing the SSID and address for the router to 192.168.1.2, plugged it into ethernet port 1, and reset the roku wireless to connect to the new SSID. After that all the issues with the Roku disappeared and things were back to normal. While this wasn't ideal it did solve the issue.