I know that this is most likely no Cwicly specific issue: When defining CPTs thru CPT UI (or other), all is fine on the backend, CPTs could be created by the FSE Editor etc… The new CPT also can be generally selected by the query block, but leads to the message within the editor:
Before spending hours in research, any hint on that that could help?
There’s something else at play. I use CPT UI and, while I have seen this error, it wasn’t because of the plugin.
Having checked on a blank installation just now, I think you may either not have the query set up, or there are no posts created.
Ensure both of those are done, and then see if the error is still there.
No problems here: https://app.instawp.io/wordpress-auto-login?site=$2y$10$Q8HFHyNee3n1N/mHG4b3yOu9ZluR/e01..OLkCx9sAGaOhS8ekiwm
Feel free to play with it.
Probably there is something messed up in my own small demo, as in the editor with the query I got this:
Does it crash or say that the block is unavailable?
This should have no consequence on the Query block as the error concerns the Section block by the looks of it.
does not crash. But I have no clue how this cpt issue is caused, a one to one comparison to your demo shows no difference
on the other hand, the creation of an inconsistency like the error above should also not be possible, at least not on such a small site I think
The “inconsistency” can be due to many factors, and user error is a cause in many cases.
Did you enter the post type yourself or select it from the dropdown list?
What are the pagination parameters you have applied?
What are the order parameters set up if different?
Is the Post Type queryable - searchable on your installation?
I will add:
If it says that it can’t find any content/posts, it literally means that the return result for the Query parameters (using the default WordPress query function) you have provided is empty.
The editor (and that query) is just working, when creating a separate custom template. My front page is somewhat messed up, I will create a new one
Interesting, I have a similar Problem but with a little bit more complex setup!
I have two custom Post Types (let’s call them “A” and “B”).
I create posts on “A” and connect them with the relationship Field of ACF (return value is post id). On the template of “A” I want to output in a Section the connected post from “B” using dynamic value!
On the frontend everything works fine. On the backend, when inspecting the query code it says “post_in => NULL”. However, I first thought that’s maybe because of the template system and it may not pick up the field value inside the editor. But then I added a static Fallback-Option, which the backend should be able to pick up in any scenario! However, the dynamic Value works on the frontend, whereas the fallback option doesn’t work on frontend and backend!
Also get the same “query content not found” message there.
Just wanted to add that. That’s also included in the list I am currently writing and will probably be a Topic in a seperated thread (wanted to make short explanation Videos for you so it’s easier to see what I mean), but I thought this somehow fit’s to that topic too! 
Cheers
