I start my app with

gunicorn app.app:app -w 2 --threads 2 -b 0.0.0.0:8080  -k uvicorn.workers.UvicornWorker

and I get error “[ERROR] Failed to add operation for GET /foo” and trying to reach endpoint in browser show “Internal Server Error”.

I have installed requirements by

python -m pip -r requirements.txt

and my requirements file:
gunicorn==21.2.0
connexion[uvicorn,flask]==3.0.6

Script code in app.py

def foo() -> str:
    return f"Foo"

app = FlaskApp(__name__)
app.add_api("openapi.yaml", arguments={"title": "Bar"})

and the important stuff from openapi looks like

paths:
  /foo:
    get:
      operationId: app.foo
      summary: Foo 
      description: Foo foo

I am usin Python 3.11.7.

what am I missing?

The api works fine when I run, no errors in the logs and the browser show expected result

connexion run openapi.yaml

The program show no erros when I run with python

python app.py

I have tried different requirements combinations of gunicorn/uvicorn/flask and tried started gunicorn with/without -k uvicorn.workers.UvicornWorker.