Your Document size will reflect your output size. If you have a visible margin with your design, this margin will translate in your output and may cause an unwanted display. Export Kit will render WYSIWYG, so all White-space is converted AS-IS.
This commonly happens when creating a bleed or full screen background for your design. Always remember your output will render WYSIWYG, so remove extra White-space.
Our Creative Team will export your project live and answer any questions you may have - we guarantee your first conversion will 100% work - we work with you to ensure this, Contact Us or check the Community FAQs for assistance.