Error: Failed to Communicate with Zend Studio

The following error message appears in Zend Server when using the Zend Studio Diagnostics that are available from the Monitoring | Events | Event Details page:

"Failed to communicate with Zend Studio. Go to the online help's 'troubleshoot' section to find out how to fix the connection"

This error message can be caused by several possible problems:

When running diagnostics on an alternate server:

• The Zend Debugger is not running on the alternate server.
  Solution - Make sure that the Zend Debugger is running and available on the alternate server. In the UI, go to Configurations | Components, and check that the Zend Debugger is loaded.

• The connection parameters in for the Zend Monitor component on the Configurations | Components pageare not the same as the settings in Zend Studio's Debugger preferences. (IP address, Port and if you are using SSL).
  Solution - Check the settings in Zend Studio for Eclipse. For instructions go here and make sure the Zend Studio for Eclipse debug settings are the same as defined in Zend Server .

• The Zend Studio IP address is not allowed to debug on the alternate server.
  Solution - In the UI, go to Configurations | Components and select the Zend Debugger component from the Components list. Make sure that the Zend Studio IP address is an allowed host to debug - the setting should be in the alternate server's Zend Server UI under Configurations | Components | Zend Debugger.