etc/event block not supported

Hey *, I've purchased the Rhythmic Pro Theme (activated as well as FSE Pro Plugin is installed and activated) and want to use the Event view as shown on your example page, but it says: "Deine Website unterstützt den „ect/event“-Block nicht. Du kannst diesen Block intakt lassen oder ihn ganz entfernen." (German) "<span class="Y2IQFc" lang="en">Your website does not support the “ect/event” block. You can leave this block intact or remove it entirely.</span>"(Google Translate) What do I have to do to make this function?! It is an essential part of the reasoning to buy this theme.   Regards