Event_source_url parameter missing

I configured everything this how to: https://gtm-server.com/facebook-conversion-api-for-shopify/

Now I get in Facebook for Page View, View Content and Add to Cart the following error:

Your server isn’t sending the necessary event_source_url parameter for your PageView events. Without including the event_source_url parameter for each PageView event sent from your server, you may not be able to use your PageView events for attribution or optimization.

This may cause issues with the attribution and delivery optimization of your ad campaigns.

How could that be fixed?

Open the Web container, click tags and check that Send common data is enabled for all Data Tags.
If it’s not enabled, enable it for all data tags, and it should fix the issue with the URL.