Report builder 3.0 - Unable to connect to server

Hi there,

We've been using Report Builder 2.0, and its been working pretty nicely. We have the option 'Use this report server or sharepoint site by default' option set to http://<server>/reportserver - and users can connect via the 'Open' dialog, save, etc.

However, some of our users have been testing Report Builder 3.0 - and they are unable to connect, even though the URL is set exactly the same.  They have Report Builder 2.0 and 3.0 installed on the same client workstation. With the same settings, 2.0 can connect, but 3.0 can not. The target installation is SSRS is SQL 2008.

The error is:

Connection failed.

Unable to connect to the server that is specified in the URL...
Make sure that the server is running, the URL is correct and you have permission to use the server.

Does anybody have any ideas?

thanks, mark