Exchange Server 2003 - Can't connect to exchange server in same machine

I have an Exchange Server running in a remote machine.

We also have an application that connects to this Exchange Server through ActiveDirectory and Independentsoft's WebDav.

This works perfectly when I run the application locally, but if I install it in the machine where the Exchange Server is running I only have connectivity with Active Directory, through WebDav I can't access any mailbox with the following URL template "LDAP://MyDomain/exchange/test@test.com", the Exist() method returns false.

Using this code:

"

var _Credential = new NetworkCredential(domain.AccessUsername, domain.AccessPassword);

var _WebdavSession = new WebdavSession(_Credential);

_WebdavSession.UserMailbox = _Url;

var _Resource = new Resource(_WebdavSession);

_Resource.Exists(); <-------

"

In the other hand, I installed the application in another machine and tried to do the exact same but I couldn't connect by ActiveDirectory, I get a "The server is not operational" (0x8007203A) error; through WebDav I get "System.Net.WebException: Unable to connect to the rem开发者_如何学Goote server ---> System.Net.Sockets.SocketException: A connection attempt failed because the connected party did not properly respond after a period of time, or established connection failed because connected host has failed to respond".

All this with exactly the same LDAP URL, credentials, and everything.

Any help would be appreciated.

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In the end I solved it, it seems to be a problem with Amazon servers: you can't connect from one to another, but you CAN connect to 127.0.0.1 (but not, for some reason, to localhost).