What kind of TV do you have? I have an Insignia and this happens to me since the last update. I have to select another input (like DVD) and then reselect Roku to get it to work. It’s really annoying. Roku has done this before with updates that affect Insignia like this. They claim it’s not the software’s fault but it is — every time.
Can you please provide more information about the issue you are experiencing? What Roku model device are you using? Have you tried performing a factory reset on the Roku device to see if you can setup the device anew?