When using Product Feed extension, there are some products files after being generated having the backend URL.
Those products having
Visibility tab is Not Visible Individually. Hence making the wrong URL generated, which means that customers at frontend cannot access the URL.
visibility to the condition of Product Filter tab by:
Store > Attributes > Product, and find attribute
Access to the configuration of
visibility. At tab Storefront Properties, with field Use for Promo Rule Conditions, select Yes.
Click Save Attribute
Go to the Product Filter tab on the feed that you need to generate and set the conditions: Visibility is not Not Visible Individually
Click Save and Continue. Then click Generate to create the file.