First step after having changed the slug:
Usage for archive loops.
Here I want to select the already existing WordPress Archive for Woongroepen.
But the only option I get is to create a new archive.
View screenshots.
Earlier, I have tried out this in staging (www.lvgo.nl/staging) and there it worked as expected.
Archives, Views, Forms, assignments of taxonomies or custom field groups, each of them when connected to some post type (e.g. a form to publish posts of some type) is connected by the post type slug.
If you change the post type slug then the form, View, archive etc thinks that the post type to which it is connected no longer exists, and it is expected that this will introduce problems.
In the case of a custom archive, the archive will no longer be assigned to any post type. The solution is to edit it and re-assign the post type in question.
Likewise a View that displays posts of that type will need the post type re-setting. Similarly forms, the assignment of Custom Field Groups, etc.
My issue is resolved now. Thank you!
I was just confused because in the previous version there was a little link under the archive name to change its usage. I found this very useful. (see screenshots)