iOS devices regard .local as a reserved domain for Bonjour applications. As such, iOS devices are not able to resolve an internal website address if it ends in .local. More details on why this occurs can be found at the following knowledge base article from Apple.
http://support.apple.com/kb/ts3389
Our best advice is to change the domain of the site being tested or to use an intermediate proxy which alters the address of the site being tested.