There is a problem with the Sketchfab preview. That is a bug you need to fix. For example, if you have this Link : https://sketchfab.com/3d-models/__lencolowpoly-__6cf80700fdfd4c58b33b8578b7fe163b , you need to delete the name of your model (the bold text!) and paste it in the field for the 3d sketchfab view.
There is a problem with the Sketchfab preview. That is a bug you need to fix. For example, if you have this Link : https://sketchfab.com/3d-models/__lencolowpoly-__6cf80700fdfd4c58b33b8578b7fe163b , you need to delete the name of your model (the bold text!) and paste it in the field for the 3d sketchfab view.