Thanks a lot for your reply.
I deactivated all Plugins except for the Events Calendar.
Used the Default Theme and no modifications.
So the error happens only on the Event posts.
On all other Sites it works well.
Hey Nick
Thanks for the answer. Sadly id din’t fix the Problem.
I tried the Timezone settings and also the Theme change. Still the same issue.
You can see it here: https://natura-handwerk.dans-art.ch/events/