Safari issue with CORS: Origin is not allowed by Access-Control-Allow-Origin

In the end this wasn't a cors issue, it was a cookies issue. Specifically it was a 3rd party cookies issue because later versions of Safari don't allow 3rd party cookies by default. Since we are the third party no cookie data was stored or passed to passed back to our server and the problem for some reason manifested itself as a cors error. Once 3rd party cookies were enabled the api calls worked as expected. Of course now we need to solve for the cookies issue.

You can Empty Caches and disable Cross-Origin Restrictions from Develop menu of your browser(for development purpose).

It worked for me.