Pandora is an HTML5 application, so it should work reasonably well on most up-to-date Linux desktop systems. Unfortunately, there are far more Linux distributions and configurations than we have the capacity to test, so we do not officially support the use of Pandora on Linux clients.
However, I recommend making sure your Firefox browser is updated to the latest version. You can try running through these steps to see if it helps: Firefox Troubleshooting
You could also try using a completely different web browser like Chrome - this will help determine whether the issue is browser-related. 🎧