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 that still doesn't clear up the issue you're experiencing, we recommend contacting the channel provider directly to follow-up for more help. They’ll be able to best assist with any issues that are occurring within their channel.
You can reach Pandora support here: https://help.pandora.com/s/?language=en_US