UPDATE: found out that my webhost provider had a Cache setting for 1 minute. When i turned that off, everything works fine!
@manthano thank you for your fast response! I guess you’re right. I found a quick fix to make the redirection work with the shortcode.
@manthano Thanks for your code. I used it on my website, but the redirect adds a /1 after the url. Any idea what I’m doing wrong?
Thanks in advance!