Integration with this Planyo site (9282) is not allowed for the current domain (en.testing.gk1.joffitours-2010.v-izdelavi.si). To turn it on, go here (Planyo admin panel / site settings / integration settings) and make sure that the domain name of the site where you are integrating Planyo (en.testing.gk1.joffitours-2010.v-izdelavi.si) is added to the 'Allowed domains' field.