Anni0502 on "[Plugin: Contact Form 7] Contact form works in preview modus but not when published"

Hi,
I have the following problem:
my contact 7 form works while I'm in the preview modus, I get the mails correctly and all is fine. As soon as I publish the article and I click on "Send", the loading symbol appears but nothing happens (no mail, no info box, just loading symbol).

Here is my article.

Has anyone got an idea?
Thanks for your help, Anja