Web Studio error: "Unable to contact EAC Central Server"

----SYMPTOMS----

You see all of the following error symptoms when using Web Studio:

a. In the Web Studio login page the following error message is displayed:
Not Connected.

b. After you log in and select the EAC Administration menu section, the following error message is displayed:
Unable to contact EAC Central Server

c. The Web Studio log file %ENDECA_CONF%\logs\webstudio.0.log (on Windows) or $ENDECA_CONF/logs/webstudio.0.log (on UNIX) contains:

SEVERE: Not Connected. ; nested exception is: 
java.net.UnknownHostException: <wrong-EAC-hostname>
OR
SEVERE: Not Connected. ; nested exception is: 
java.net.ConnectException: Connection refused: connect


----CAUSE----

The Web Studio properties for the EAC Central Server are configured incorrectly.


----RESOLUTION----

1. Stop the Endeca HTTP service.

2. Open the webstudio.properties file located in %ENDECA_CONF%\conf (on Windows) or $ENDECA_CONF\conf (on UNIX).

3. Locate the EAC Central server properties, for example:
# The EAC Central server that this WebStudio uses
com.endeca.webstudio.eac.hostname=<EAC-hostname>
com.endeca.webstudio.eac.port=<port-number>

4. Set the value of the properties to the correct value, for example:
com.endeca.webstudio.eac.hostname=eacserver
com.endeca.webstudio.eac.port=8888

5. Save and close the webstudio.properties file.

6. Start the Endeca HTTP service.