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.
Try doing a manual System Update to your Roku. (This updates both Roku Software and installed Channels). Normally, I follow with a System Restart of the Roku.
Settings..System...System Update...Check Now
Sometimes, Channels/apps just experience some temporary issues and will begin to work again with no end-user action. Could be Prime or Netflix servers experiencing an issue or could be issue with the Channel/app. If Updating the Channel, or Uninstall, Restart, Install Channel again, and modem/router restart doesn't solve issue, then normally give it a few hours or a day to resolve.
I have even found that a particular Channel/app may not temporarily work on my RokuTV, but will launch and work fine on another Roku device. It then begins to work on the other offending device (normally the RokuTV) later in the day without me doing anything.
Roku Community Streaming Expert Just another Roku user... I am not a Roku employee.