Hi there,
Using the browser dev tools, I checked the product images that it was trying to load for a few of your products. However, opening those URLs on their own (in other tabs) was resulting in 404/Page Not Found errors:
https://flexenergy.org/wp-content/uploads/2020/05/Coal-Stove-Jikokoa-247×296.png
https://flexenergy.org/wp-content/uploads/2014/08/PRO-247×296.png
Please check the Product Images set on your products and make sure they are pointing to images that actually exist.
If you are still having trouble, please share a copy of your site’s System Status. You can find it via WooCommerce > Status. Select “Get system report” and then “Copy for support”. Once you’ve done that, you can paste it here in your reply. Please note that since this is a public forum, you may want to remove any sensitive information that you don’t want shared publicly.
Thank you!