I have an Office 365 account and I am trying to create a SharePoint App via Visual Studio 2013 Here are the steps:
1. Open VS 2013 and select Office/SharePoint > App for SharePoint (type the name) then click OK
2. I type in URL of the site (of course https://) and Select SharePoint-Hostedoption, then click Finish
3. I get the Office 365 authentication dialog box.
I type in the username and password and it opens the SharePoint in the same rectangular dialog box and it stays there and nothing happens:
If I click the close icon on the Connect to SharePoint dialog box that still shows my SharePoint online site, I get the following error: 
If I click on OK I get the Connect to SharePoint dialog box again
