If there is a proxy server between your client device and the MetaFrame servers, you must enable auto proxy detection, as described here, or manually specify a proxy.
To enable auto proxy detection, select Use Web browser proxy settings. The ICA Java Client tries to obtain the proxy server details from the Web browser.
Note: The ICA Java Client cannot obtain proxy server details from all Web browsers. For a list of supported browsers, see the Citrix ICA Java Client Administrator's Guide.