With WC 3.0 they removed the support of gallery/popup/lightbox on WooCommerce product page.

To Add support for gallery/popup/lightbox on WooCommerce product pages, please try to add following code lines to theme’s functions.php file:

add_theme_support( 'wc-product-gallery-zoom' );
add_theme_support( 'wc-product-gallery-lightbox' );
add_theme_support( 'wc-product-gallery-slider' );