Error using Smush.it. and Domain Mapping

Hi there,
I've just installed Smush.it. While making a test on one image from the media library I've got the following message:
"ERROR: http://charoiglesias.losnuevosartesanos.com/wp-content/uploads/sites/3/2014/06/Charo-Iglesias-Sombreros-de-boda_261.jpg must be within the website home URL (http://www.charoiglesias.com)
Re-smush"
As you can guess I use the Domain mapping plugin. But then how can I make Smush.it works so it knows that charoiglesias.losnuevosartesanos.com & http://www.charoiglesias.com are the same...

Thanks for your help