When on mobile, I usually come from using another app to the Roblox mobile app. When I previously use another app (such as Google or YouTube), and go to Roblox, its sound breaks and games become silent as there is no audio. This becomes very annoying as I have to restart the Roblox mobile app to fix it. I don’t know if Roblox or the other apps are at fault here.
Sorry about the wrong category, I didn’t know which category to pick whilst reporting this bug, but this is a mobile bug. 
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Thanks for understanding!