Once the preview mode is enabled, click the event (on the left side) when your GA4 tag was supposed to fire. If you have set the tag to fire on All Pages, it means that you need to click Container Loaded.

This has nothing to do with Google Tag Manager’s variables. The Variables section in the GA4 Free Form reports is the place where you select data that you plan to use in a report: Date range.

In order to use the ValueCheck App, you must already have an active account with Carauktion AG.