Hi all, I'm in the process of learning Reporting Services and as advised by some here I'm getting my feet wet using Report Builder - all is good ( creating reports etc ) except I can't connect to to my Report Server from Report Builder - I can connect to it using a browser but I receive an error when I try it from Report Builder

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. 

SS and the Report Server are both installed on my laptop so I don't know why I can't connect. I'm using SS 2014 Express and Report Builder 3.0