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.
Do you have a subscription/account with the channels that you are trying to watch content on?
Try removing the channel from the Roku home screen by navigating to the channel tile, pressing the * key on your remote and choosing 'Remove channel'. Then restart your device from Settings>System>System restart. Once your player starts up again, add the channel back once more.
If the issue remains unresolved, I'd recommend reaching out to those channels support directly to report the issue and request additional support. Many channels on the Roku platform are developed and maintained by the channel provider directly, and they'll be able to best assist. If other channels are working correctly, and you only experience this issue on those channel (app), that is likely an indication that the issue lies within those particular channels. In these cases, the channel provider will need to investigate the issue in order to help resolve it.