If the design is out of safe area, the contents will not show on the final product.
Safe Print Area
Keep your design elements within this area. Pattern elements are actual representation of your finished product, not a mockup. Text or graphics outside of this may not appear on the final product once sewn.
The contents on the Men's Tee are outside the safe print area. They can be seen in the mockups, but not in the final product. If the words "kincustom" is designed outside the safe print area, while all mockup images in Creator Studio show the words, in the final product, the words are gone between sizes XS - XXXL. The design would be partly gone by cutting and stitching.