WSDefinitions problems

Hello ! I am trying to call a method from a webservice.
On the desktop platform, it is working very well, but on the mobile platform I get this error : "Error calling constructur(WSDefinitions): User authentication failed. Service URL: ***url***".

Why is it working on desktop and not on mobile ? WSDefinition is available for mobile app( Server ).

My error is on the line with "New WSDefintions".

Address = ***;
Username = "admin";
Password = "admin";              
URI = "***";
ServiceName = "MobileApp_Service";
EndPointName = "MobileApp_Port";
Try
Definitions = New WSDefinitions(Address, Username, Password,,,, True);      
Proxy = New WSProxy(Definitions, URI, ServiceName, EndPointName,,,,, True);
Proxy.User = Username;
Proxy.Password = Password;

Hello, Sebastian!

I suppose that the problem is that you set the UseOSAuthentication parameter to True and it works for you on Windows, but does not work on Android or iOS device.