Description
When using the ArcGIS API for Flex, an ArcGIS Server task or service is not accessible.
Cause
If the ArcGIS server and Flex application are not hosted on the same Web server, the ArcGIS server needs to have a crossdomain.xml file in the root directory.
Solution or Workaround
For security reasons, the Web browser is not allowed to access data that resides outside of the exact Web domain where the SWF file originated. However, the Adobe Flash Player can load data across domains if permission is granted from the server. This is accomplished by having a small crossdomain.xml file on the remote server that permits Flash to connect to services on that server.
To deploy the cross-domain file on ArcGIS Server 9.3 and later, see the instructions specific to your platform below or visit the Resource Center help (Concepts > References > Using crossdomain.xml).
For additional information, read about Using cross-domain policy files, see the Adobe TechNote, "External data not accessible outside a (Macromedia) Flash movie's domain," or view a sample cross-domain file.