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.
I understand that you are unable to access the Tennis channel and asking you to sign in/up again, is that correct?
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. Please make sure to enter the correct channel login credentials.
If that still doesn't clear up the issue you're experiencing, it's best to reach out directly to get the channel going on your Roku. They can resolve the error you are having with the channel login. Please be noted that Roku doesn't manage channel logins or authentication and many channels on Roku are developed and maintained by the channel provider themselves.