I understand that. But its always better for me to see your app’s build.settings.
But regardless change:
["plugin.mediaBrix"] = { publisherId = "com.coronalabs", supportedPlatforms = { iphone=true, android=true } },
to
["plugin.mediaBrix"] = { publisherId = "com.coronalabs", },
or
["plugin.mediaBrix"] = { publisherId = "com.coronalabs", supportedPlatforms = { iphone=true, android=true, ["iphone-sim"]= true, } },