Sound effect not working

Hi Team, The sound effects on both my kiddos accounts don’t work. For background, they each own an Android tablet (Lenovo 10) and I have enabled Family Link to monitor the app download on their tablets. I have ensured sound effects stands enabled in Khan Academy settings on their tablets as well as through my own Khan Academy account (parent dashboard) but still the sound effects don’t play. The Khan Academy video volume plays fine though. It’s just the sound effects that don’t work. And I’d really like to get this enabled as it adds to their motivation when getting a sum right. Please help.