Moved a web site from a windows 2008 R2(IIS7) server to a 2012 R2 server running IIS8.5. 

This web site uses jquery.jsonp strategy to access a web service on a different domain. 

It doesn't work anymore. In fact any web site on the 2012 server will not access any url from a different domain even if the different domain web site is on the same 2012 server or on the old 2008 server. The same site works from the old server or from a development machine running windows 10. Both of which will find, access and authenticate the web service site on the new 2012 server.

It behaves like there is some kind of security setting in windows 2012 or IIS preventing cross domain access.