Audio problem with Sonic Pi on Linux

Hello. I have started my lessons with Sonic Pi (2.10). My operating system is Ubuntu 18.04 and 8 have a problem with the sound. The app works fine but I can’t listen what I just wrote in the script. Can anybody help? I am afraid that a driver might be missing and I cannot uninstall the app because the system doesn’t let me to. Any ideas? Thanks in advance…