The configured proxy server was unable to establish a connection.

The following occurrence messages I have encountered when the ICA Consumer is unable to get an instruction MetaFrame Show Computer or Secured Gateway server through a proxy server”
"The configured proxy server was unable to establish a connection”
The notes related with apiece error content are planned to be head guidelines only. I have not encountered this problem before. If anyone knows how to solve this, please guide me how to fix it. Thanks in advance.
