Dynamic Web Content in WordPress

Your software
My Mautic version is: 3.3.3
My PHP version is: 7.4
My Database type and version is: MariaDB10.14

Your problem
My problem is:
Dynamic Web Content is not rendered on WordPress Website.

These errors are showing in the inspector:
204 error - no content

Steps I have tried to fix the problem:
Used the WP Mautic Plugin with shortcode,
Used the “

” method from the documentation
The dwc is published and not campaign based.
I tried several filter variantions. It seems that I miss something.
I know it worked a while ago.

Does anybody use DWC with WordPress anymore? How are you doing it?

PS: On an a Mautic landingpage it works as expected.