Cannot connect to remote Citrix Server

[Max_Guard]

Hi to all, I installed and setup Pfsense+Squid+Squidguard, everything goes well except for connecting to remote Citrix Server. Initially I can log in, but when I click the publish apps, there's an error message that says "…. Cannot connect to the Citrix Xenapp. There is no Citrix XenApp server configured on the specified address." Please help on this.