1. my C2 game is hosted on site A. Site B is displaying my game (from site A) inside iframe. on google chrome on Android devices no sounds are playing because of permission problem.
2. On mobile my games are not really on full screen (can see status bar), I need a code that can recognize the status bar is there and suggest the player to scroll bottom-top the screen to get it to full screen. you can see an example of how it should work here:
https://netent-static.casinomodule.com/ ... ule.com%2F <link is broken
load it on mobile and see when on landscape with status bar it will display an hand gesture suggesting you to turn it to full screen by swiping up.
Problem 1: if your site B has https it will partially load/majority of times never loads from any other hosting that isn't https or secured.
Problem 2: Depends what you are using to wrap your mobile apk or ios pack it should have a code for the compilation there usually for android you can find it on android.com or .org forgot the main website its in there in the manual to show or hide status bar(clock/battery etc)
your audio problem is probably caused by the HTTPS certificate try hosting your app on same website ur loading it on. or on a https hosting service. (also if your iframe loads a C2/c3 html game/app make sure you dont have adblock enabled usually it blocks iframes and apps like c2 html5 games etc.)
if your not aware yet, since 2016 or ios 8 fullscreen and autoplay doesn't work anymore on ios devices, it requires user input that means you cant have a script that loads some music or video that users dont give their consent to play, that includes auto fullscreen.
for android if i remember correctly still works, however it depends on browsers... i recommend using chrome for your c2 tests and not Mozilla its probably not what your client wants to hear, but he needs to realize problems that are there and C2 cant bypass them, because its not c2 fault, is browser/device fault or security.
that being said ... i think you have some other issue even though i guess i answered to what you asked. but if its not the case please update your problems in a more precise detail.