Error ID should not be empty

Hey there we are setting up the join API for our client and are blocked on an issue.

Any post call we make for create application gets the same response "type": "Validation", "message": "id should not be empty".

We can't find the ID it's referring to and this also happens when we test this directly in the API so it's not related to the implementation. Can you point us to what this ID is we need to set and how it should be set?

Steps to reproduce:

Go to https://docs.join.com/reference/createapplication
Set header credential value (maybe it's related to our value but it worked fine for getting the jobs?)
Select php as language
Click on examples selector and select Request Example
Click on Try button
You should get the same validation error message "type": "Validation", "message": "id should not be empty".