However, I'm facing with the following issue: when running the script with one Virtual User, it works, but when I run it with 2 Virtual Users, I receive a warning for the request corresponding to the page that does the login. As far as I could see, the difference between a a successful test and a failed one is the following:
The difference is that in the first response header the server redirects the client to the "AdministratorHome.aspx" page, while in the second case the server returns the requested page and does not redirect the client.
So, the question is: Why does the server redirect the client when it asks for a page? How does it know when the client needs to be redirected?
The answers to these questions are related to the logic of your server application's functioning. You need to find this out to understand why the server gives different answers to different virtual users.