We are currently running a 2 server exchange environment with Edge services on their own. We are in the process of trying to deploy a piece of software that uses the EWS API which has brought me to this form, the software ties into the EWS service and uses it to forward messages (this is failing). Using the software error logs I have found that accessing EWS from the exchange server is not possible. From my work machine and an external address I can type the following https ://webmail.companyname.com/ews/exchange.asmx and be prompted for a username and password, once I enter credentials I get a screen full of information from services.wsdl. The problem is when I try the same URL from the exchange server and get the credentials prompt I cannot get past it. Even with the same credentials that work externally and from my desk it just keeps looping around. Capture from software log (11:41:32.6415 000017e4 System.Net.WebException: The request failed with HTTP status 401: Unauthorized.) I have also found the same results when trying https://webmail.companyname.com/ Autodiscover /Autodiscover.xml . Environment Information Server 2008 STD 64bit Exchange 2007 SP1 Purchased Cert – webmail.companyname.com I have also confirmed that all services have the proper internal and external URL’s. Any help would be appreciated.