On my Contoso environment I was trying to create a sandboxed solution. I have already configured my app domain and app management services. But when I tried to validate the site I got the following error message.
Cannot connect to the targeted site. This error can occur if the specified site is not hosted on the local system. SharePoint solutions work only with locally-installed versions of SharePoint Foundation or SharePoint Server. Remote development is supported only for apps for SharePoint 2013.
If you search around the internet you will find many people suggesting to change your host file from 127.0.0.1 to the actual IP.
SolutionHowever the solution, at least on a Contoso environment, is to type in the actual IP address in the host file.
(the IP 192.168.150.1 is the special IP for Contoso, I have 2 network adapters)
And do not forget to clear/flush the DNS cache.