> But in two of the networks, the server is configured using Active Directory and a domain (I am not an expert on this subject). In these cases, the application is much slower. When it starts, it lasts 40 seconds to show the window to type username and password and afterwards, in every other query it makes, it is slower.
>
> What may be causing this?
>

First thing that comes to mind:
Do you have the servername in the connectionstring?
If so, what happens if you use the ip nr of the server instead?

John