Flask POST returning 400 in production

Question

I am building some POST endpoints in my code.

The problem is that they work fine in testing, using pytest with flask test client, but they don't work at all with outside requests originating from cURL or python's requests module.

I have done A LOT of testing and I couldn't figure out why flask is throwing the 400 error. Does anyone have any idea what might be going on?

Endpoint:

@api_blueprint.route("/tibiacoin/confirmation", methods=["POST"])
def tibicoin_withdrawal_confirmation():
    content = request.get_json(force=True)
    withdrawal_id = content["id"]
    withdrawal_status = content["status"]

    if withdrawal_status == "OK":
        withdrawal_object = TibiaWithdrawal.objects(pk=withdrawal_id)[0]
        withdrawal_object.is_processed = True
        withdrawal_object.save()

    response_dict = {"status": True}
    return jsonify(response_dict)

Test pytest:

@pytest.fixture(scope='module')
def create_flask_app():
    #drop all records in testDatabase before strting new test module
    db = connect(host=os.environ["MONGODB_SETTINGS_TEST"], alias="testConnect")
    for collection in db["testDatabase"].list_collection_names():
        db["testDatabase"].drop_collection(collection)
    db.close()
    
    # Create a test client using the Flask application configured for testing
    flask_app = create_app()
    return flask_app

@pytest.fixture(scope='function')
def test_client(create_flask_app):
    """
    Establish a test client for use within each test module
    """
    with create_flask_app.test_client() as testing_client:
        with create_flask_app.app_context():
            yield testing_client 


def test_withdrawal_confirmation(create_flask_app, test_client, data_sample_tibiacoin_api):

    payload = {
        "id": "",
        "status": "OK",
    }

    response = test_client.post('/api/tibiacoin/confirmation', json=payload, headers=headers)

    assert response
    assert response.json["status"]

test response:

OK

Actual requests:

import requests

payload = {
        "id": "",
        "status": "OK",
}

r = requests.post('http://localhost:5010/api/tibiacoin/deposits', json=payload, headers=headers)
print(r.status_code)

response:

400