Splash Connection refused on target localhost URL

Question

I am trying to render JS with Splash, it works with normal URLs like https://google.com, etc but it does not work for URLs having addresses like http://localhost:8002/report.

Error:

{"error": 502, "type": "RenderError", "description": "Error rendering page", "info": {"type": "Network", "code": 1, "text": "Connection refused", "url": "https://localhost:8002/"}}

I.e: curl 'http://127.0.0.1:8050/render.html?url=https://localhost:8002'