Finally got a chance to try this on iphone. I reproduced the issue you found. What happened with me is this: attempting to load https://launch.playcanvas.com/896727 caused the playcanvas login screen to pop up. After entering my details and logging in I was met with the error loading ammo.
However the browser had taken me to https://playcanvas.com/editor/scene/896727/launch instead of launch.playcanvas.com/896727. The former URL doesn’t work at all, not even on desktop chrome, but after re-entering the correct launch URL it worked fine.
Please could you check whether the same is happening to you? Make sure you’re logged in to playcanvas and then navigate to the launch URL. I guess the playcanvas.com login screen has a legacy URL that should be updated.
@vaios do you have any idea what may be happening here?