I can't say what's wrong because it works just fine for me.
Here is screen shot of the instructions.
Hi @embram,
Thanks for posting in the Roku Community!
We're sorry to hear about the playback issue that this may have caused. That's not what we aim for. In some cases, removing the affected channel and re-installing it may help. To ensure the process is successful, follow the steps below, making sure you restart your Roku device before adding the channel again.
If, after attempting the suggestions above, you are still experiencing the same issue from a single channel while content from other channels plays fine, contact the customer support team for the channel provider to report the issue and get help. Many channels on Roku are developed and maintained by the channel providers themselves.
You can reach them here: Classic Reel Support.
Please keep us posted, and we'll continue assisting you from there.
All the best,
Chel