@BENISTI, DANIEL Thanks for reaching out.
400 Bad Request means that the request could not be understood by the server due to malformed syntax. The client SHOULD NOT repeat the request without modifications.
In your case please validate whether you are passing the request body, header and query parameters (if any) correctly while calling your API with the Native HTTP connector for logic app.
To troubleshoot it further I will suggest you to use any REST client, fiddler/postman to create the request and validate it with your configuration that you are passing in the HTTP connector.
In case if you are still facing the issue then please let me know so I can validate your fiddler/postman and configuration in your HTTP connector to assist you further.