Help & troubleshooting for channels on your Roku device, including adding/removing channels, logging in to, authenticating, or activating a channel, channel-specific playback issues, assistance contacting channel publishers to report issues, and adjusting channel-specific settings.
Whenever you uninstall a Channel, you need to do a System Restart of your TV (settings..system...power...system restart) before reinstalling the Channel back to your TV.
If still doesn't resolve the issue you are having, you are going to have to contact the developer of the channel. See if there is some sort of contact link or email address. Since this is a non-certified channel, could be experiencing problems for a number of reasons. I couldn't easily test this channel (out of region) for you. In the alternative you may be able to press the *button on your remote and send feedback to the developer (ie. channel fails to launch).
You can also try contacting Disney+, not sure if this is their unofficial workaround or not. Web reports differ. Kind of doubt it, but they may have info if an issue exists that they are aware of. https://help.disneyplus.com/csp