The settings for the Design Editing Area in Craft Designer Admin are not suitable.
Try re-setting the Design Editing Area. Shoot a photo of the actual item for the background image to help the customer visualize the print result.
Changing the Design Editing Area
Note the following points when shooting a photo.
Shoot in a well-lit area that is not backlit
Shoot from the front of the item
Shoot the photo so that the entire image is visible
The size of the Design Editing Area differs from the actual printed size.
See the following procedure for details on setting the actual print size.