If the live streams are not working on any of the Roku boxes you have, then you will need to adjust the box Settings related to display type.
After plugging it in and hooking up the typical audio/video connections, there’s a simple on-screen wizard to follow. Go to Roku Player Settings:
Select Display Type option – by default they are set to 720p for standard definition TV.
The VODs (videos on demand) are working no matter which is the the setting or the video resolution.
For viewing live broadcasts, you will need to set the above settings to any HDTV (either 720p or 1080p), like in the following image: