API RPC Returning Login Screen

[RhysL]

SYSTEM
Plesk Panel 9.5.4, Windows Server 2003 (5.2; SP2.0)
VB.NET 2.0

PROBLEM
Whenever I send a packet via HTTP request to the Control Agent, it simply returns the HTML to the login page for the control panel.

Doesn't seem to matter what I send, I've even been trying to produce an error so I can handle the returning packet. I have followed the developers reference to a 'T' with unsuccessful results.

However, if I access the Control Agent [###:8443/enterprise/control/agent.php] directly, as expected it returns an XML packet containing error information.

Initially I had this problem with Panel 9.3.0, so I upgraded to 9.5.4 with the hope of it fixing the problem, as I had read that another person earlier had the same issue, but after upgrading it fixed the problem. Unfortunately I am not so lucky, and upgrading (and restarting Plesk afterwards, twice) has not fixed the problem.

Please, anyone with any clues, please help.

 

[RhysL]

VB.NET Expecting Response of 100

After scouring other forums and using Google's helpful translate service (from German), I was able to find the solution to my problem.

SOLUTION
This is in VB.NET which is the environment I am working in:
ServicePointManager.Expect100Continue = False

Without going into details, .NET defaults this setting to True which means it changed the header removing the authentication details. The HTTP request expects a 100-Continue response from the server. Obviously this isn't going to work.

For further information on the class: ServicePointManager.Expect100Continue Property