Unable to Activate MS Project 2010 Pro

This was an interesting issue that I came across. We had a team piloting MS Project Server 2010 and we provided MS Project 2010 Pro for project managers. 

Initially we began with trial version and it expired after the limited days. We then decided to use the volume licensing copy. The media remained same for all the installations. And below is the scenario.

1. All the users had Windows XP

2. All the users had trial version of MS Project 2010 Pro installed

3. We uninstalled the trial version. Installed the full version later using same media.

4. Activated the product using Internet.

Problem:

Out of all those installations, it went wrong for one user. It showed an error message as below.

An unspecified error has occurred. Your request cannot be processed at this time. Please try again later ( 0x8004FC12)

Solution:

We tried multiple time with reboot and it didn't help. Finally went through Premier Support of Microsoft. Had the solution and it was damn easy which we didn't think. There existed a proxy configuration on I.E that blocked the user having the installation activated. 


Caution: 
This works when the identified problem is on IE Proxy Settings. If you have proper proxy settings and still the error appears, I would strongly recommend to take support from the product support group.
Also changing the proxy configuration of IE may result in interrupting your other day to day work. Purpose of this post to share the experience that I had.

Let me try to edit this post later to add more information. But basically you have the solution for this scenario for now.