My logo is not visible on the product?

Short answer: The logo color is too close to the product color. You need a negative version or a version with an outline.

Cause

The logo blends into the color of the product it is placed on.

Two options, both to ask your graphic designer for:

a negative version of the logo (colors inverted or changed);
a version with a white, black or other-colored outline, which lifts the logo off the product.

Then upload that version as a logo in its own right and set the matching background — see Light background or deep background — which should I choose.

Plan ahead: ask for this version from the start. See What should I ask my graphic designer for.