Content is not shown in WordPress
I have a problem with H5P and WordPress. The Content is not shown in the Frontend.
First of all my system:
Desktop with Firefox, Opera and Edge testet
WordPress Version 5.5.3-de_DE
H5P Version 1.15.0
H5P is fresh installed.
Discribtion of the Problem:
In the backend I can create all kinds of content types. I can see them in the Backend, can test them, modify them, delete them. And I can see, that H5P is realy what I want. But if I try to insert this content in my Frontend-Page while using
[h5p id="15"] as a Shortcode, it is not shown. Well, sometimes it is shown for a wink, but just for less than a 1/10 second, before it is canceled. I tried several codes and several different Templates/Themes. If I use a Shortcode, which does not exist, I become a Message shown, that "H5P content with id: 4 can not be found". (Ok, I become this message in German).
My question is, where my mistake is. I would like to start using H5P but I have to see the content on my frontpage.
If you have any Idears, I would be glad if you can help me (or give me a link if I have not seen this problem in another forum).
Regards (and sorry for my bad English)