I cannot hear any sound on chromebook

This year, my whole class got hp cromebooks. so we wanted to download muse score to write music, but we both seemed to have a common problem. No matter how many times ichecked the speakers and volume, the program did not make any sound. The computer's spearker work fine with other sites. We had to download the program through "rollapp" I'm not sure if that effects anything in the situation. If you could please help me with this problem, I would greatly appreciate it. Thank you very much.