This was referenced after finding a MS hotfix article.
To make the list for pass through authentication
- Click Start, type regedit in the Start Search box, and then press ENTER.
- Locate and then click the following registry subkey:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\WebClient\Parameters
- On the Edit menu, point to New, and then click Multi-String Value.
- Type AuthForwardServerList, and then press ENTER.
- On the Edit menu, click Modify.
- In the Value data box, type the URL of the server that hosts the Web share, and then click OK.Note You can also type a list of URLs in the Value data box. For more information, see the “Sample URL list” section in this article.
- Exit Registry Editor.
This started working straight after i did this. The article says that you have to restart the Web Client but it worked right away.