CustomGPT Action doesn't work with FastAPI Rest-Endpoint

[sebi.essling]

Hi there,

I have created a customGPT and want to add some Action. Therefore I developed a very small API (for testing at the moment) with FastAPI and hosted it on Vercel.

This is my very small OpenAPI Scheme:

{
  "openapi": "3.1.0",
  "info": {
    "title": "FastAPI",
    "version": "0.1.0"
  },
  "servers": [
    {
      "url": "https://hxminsights.de/"
    }
  ],
  "paths": {
    "/": {
      "get": {
        "summary": "Root",
        "operationId": "root__get",
        "responses": {
          "200": {
            "description": "Successful Response",
            "content": {
              "application/json": {
                "schema": {}
              }
            }
          }
        }
      }
    },
    "/profile": {
      "get": {
        "summary": "Get Profile",
        "operationId": "get_profile_profile_get",
        "responses": {
          "200": {
            "description": "Successful Response",
            "content": {
              "application/json": {
                "schema": {}
              }
            }
          }
        }
      }
    }
  }
}

In Browser or Postman it works fine.

But Chat-GPT always send me following response:

If I’m checking the Runtime Logs on Vercel there is nothing. So it seems that ChatGPT isn’t send anything. There is no authentication so far. Anyone has an idea? For me this Actions look very unstable…

kind regards