Unable to access TFS OData url

Hi,

I wanted to get all the projects in our tfs instance using odata url.

But when I execute this url -  https://{server_name}/DefaultCollection/Projects  in browser, I am getting the error - it is not able to get connection to the server.

But i am able to access the web portal https://{server_name}/tfs.

Please guide me if am doing wrong, I want to see all the projects in my server using tfs odata url.

Thanks in advance

Remya