Appears that the RumbleTV Channel/app will be deprecated and removed shortly from the Roku platform by the Channel Developer.
Rumble used to offer both the Rumble and the RumbleTV Channel on Roku. (https://channelstore.roku.com/search/rumble)
These were essentially the same Channel/app. If you haven't already, just install the Rumble Channel on your Roku to continue using Rumble. (https://channelstore.roku.com/details/9d7828c984f24d379ee54f2f2028361f/rumble)
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