Issue with an HTTPRequest not working like the same request in Postman

Godot Version

4.4

I have a weird issue with an HTTPRequest. I need to contact a SaaS service. I’m making the request with Postman and with Godot. I’ve tested my requests on httpbin.org and made sure both requests were exactly the same (as much as httpbin can tell me). The request works fine on Postman but not with Godot.

The SaaS service is (https://)app.drime.cloud/api/v1/uploads with method POST, if some of you want to test (it returns a 405 status code with Godot but it’s fine with Postman). I’m quite puzzled and have no clue how to investigate this.