It just took a little bit to load (a little longer than usual). I pressed FF and it seemed to trigger it showing on screen. Once it starts to stream you will have to further FF until 15 min or so before you get actual video. (This was a livestream, so first 15 min with just "Starting Soon" page with contributors/donor list scrolling. (3hr 47min total)
All the other videos on the Donald J. Trump subscription seemed to work fine.
FYI, for the rallies, RSBN is always a good one to follow.
I watch alot of Rumble and sometimes Rumble itself just has some issues and the creators even some issues getting their videos to work on the Rumble Channel. Normally, if you are experiencing an issue with Rumble on the Roku platform, see if you watch the creator on the Rumble website and cast it to your Roku. (alternatively, laptop with hdmi cable directly to your tv).
Good to get into the habit of finding various ways to stream your content to your TV in case there is an issue with the Channel/app or if something more nefarious occurs in the future.
In this case, though, it appears to be working - just taking a bit of time to load content.
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