How to deal with transfer encoding in Python?

I am working on an analytic API for small ML project. I have created an endpoint, which uses Flask's stream_with_context function like in the example below:

def post():
       # some logic
       [...]

        try:
            res = get_data_from_elastic()

            def generate():
                for hit in res:
                    resp_dict = {
                        "timestamp": hit.timestamp,
                        "user_id": hit.user_id,
                        "node_id": hit.node_id,
                        "loc": hit.loc,
                        "is_target": hit.is_target
                    }
                    yield json.dumps(resp_dict) + '\n'

            return Response(stream_with_context(generate()), status=200, mimetype="application/json")

        # except:
           # some exception handling

It's not an exact extract from my code, but the generator works the same. I use Python requests to connect to the API, with the following code:

response = requests.post(analytic_api_url, 
                         headers={'Authorization': token}, 
                         data={'since': since,'till': till})

When I connect to the API and download small amounts of data at once, everything works fine. Unfortunately, when I try to download bigger amount of data at once, I am getting the following error:

ChunkedEncodingError: ("Connection broken: InvalidChunkLength(got length b'', 0 bytes read)", InvalidChunkLength(got length b'', 0 bytes read))

As the error is about chunked encoding, I've checked things like setting Transfer-Encoding: chunked header in the server's response, I've also tried using stream=True parameter from the requests library - none of these solutions worked. How should I deal with this problem? Should I explicitly set some other Transfer-Encoding header, or create another generator for my API?

Thank you for your help!