Thank you for getting in touch with your question. I've taken a look at your Facebook Shop and also see the 404 error message when I click the "View on Website" button for products listed on Facebook.
I noticed when I did this I was redirected to your custom domain (www.chillmamasboutique.com), but when I visit your storefront directly, I can see that the default myshopify.com URL is shown as the primary domain (chill-mamas.myshopify.com). This would lead me to suspect the issue may lie with your custom domain.
Can you please tell me when you added the domain to your store, and if you bought the domain directly from Shopify? When you head to Settings > Domains in your Shopify admin, do you see any message other than "Connected" in the Status column?
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