Sometime the SKUBubble Product’s variant attributes are different from Channel’s variant attributes. In this case you have to do mapping between them to push SKUBubble to that channel.
Here you can find the steps to set the mappings between your custom product options and channel specific attributes/fields.
Clicking on Products -> All Products menu at the left menu bar or All Products in the middle of dashboard page take you to the manage products page.
Click on title of the product for which you want to do the attributes mapping.
Click on Variants tab. he Variants Tab. Here you can setup the mapping and click on Save button.