Sending the form requires Login

Hello,

we made a form (which was as easy as described btw), but users cannot send in the form because it requires a login.

If we (logged in admins) send the form everything works as expected and we do receive the email with the content the user submitted.

I′ve searched a lot, but as far as I can tell this should not be standard behavior, and there normally is actually a plugin needed to get this (for us unwanted) funktionality.

How can we set-tup the form in such a way that it doesn′t require the user to be logged in?

Kind regards

The page I need help with: [log in to see the link]