MDS HttpWebRequest WebException RemoteServer issue

Here is a small description of the issue:

I have in my box Windows Server 2012 64-bit, SQL Server 2012 SP1 64-bit and SharePoint 2013.

After installing and configuring MDS on my server, I can go to the web app’s home page but if I click on the Explorer (or pretty much anything running SilverLight), I get the following error:

MDS_HttpWebRequest_WebException_RemoteServer

 

Then I downloaded and install the Excel Add-in for Excel 2013, but when I try to connect to the server, I’m getting this error:

MDS_Add_In_Excel

 

After hours of more research, and lots of patience I finally was able to solve a very weird issue with Master Data Services.

It turns out that that for some odd reason, the applicationHost.config file located in the windows/system32/inetsrv/config folder  was missing a XML tag for the MDS ‘service’.

1) Make sure you have all the MDS Web Application requirements installed on your server: http://msdn.microsoft.com/en-us/library/ee633744.aspx

2) Make sure you created your site with the MDS Configuration Manager and that you in fact can browse the Home Page.

3) You need to have Admin permissions and edit the windows/system32/inetsrv/config/applicationHost.config file to make sure it contains the following tags:

<location path="MDS">
 <system.webServer>
  <security>
   <authentication>
    <digestAuthentication enabled="false" />
    <basicAuthentication enabled="false" />
    <anonymousAuthentication enabled="false" />
    <windowsAuthentication enabled="true" />
   </authentication>
  </security>
 </system.webServer>
</location>

<location path="MDS/Service">
 <system.webServer>
  <security>
   <authentication>
    <basicAuthentication enabled="false" />
    <anonymousAuthentication enabled="true" />
    <windowsAuthentication enabled="true" />
   </authentication>
  </security>
 </system.webServer>
</location>

If I have to guess what exactly caused the issue, I’ll say that the ‘Service’ tag gets created the first time you create a site, so if you for any reason end up deleting or creating another site, IIS is actually not updating this file. But, that’s just my guess.