Python CRON google flexible app engine not working - python-3.x

Question

I have the following cron.yaml:
cron:
- description: "TEST_TEST_TEST"
- url: /cronBatchClean
- schedule: every 2 minutes
And then in app.yaml:
service: environ-flexible
runtime: python
env: flex
entrypoint: gunicorn -b :$PORT main:app
runtime_config:
python_version: 3
With this as main.py:
from flask import Flask, request
import sys
app = Flask(__name__)
#app.route('/cronBatchClean')
def cronBatchClean():
print("CRON_CHECK", file=sys.stderr)
return "CRON_CHECK"
When I type in the full URL, I receive "CRON_CHECK" on screen but this doesn't seem to be executing. Also in App Engine dashboard, when I click on CRON jobs there aren't any listed.
Any help in getting this to execute would be much appreciated,
Thanks :)
EDIT 1
I now have the cron task executing but I'm receiving a 404 error. When I type the full URL (that is - https://.appspot.com/cronBatchClean) the respective code executes.
I added a GET handler but I'm still not receiving any luck.
#app.route('/cronBatchClean', methods=['GET'])
def cronBatchClean():
print("CRON_JOB_PRINT", file=sys.stderr)
return "CRON_CHECK"

Answer 1

In the cron.yaml there are unnecessary “-” characters, that are starting the new list. YAML Syntax
Correct format for Cron Jobs cron.yaml, see Google Cloud documentation:
cron:
- description: "TEST_TEST_TEST"
url: /cronBatchClean
schedule: every 2 minutes
To deploy Cron Job use gcloud command :
$ gcloud app deploy cron.yaml

Answer 2

To solve this problem i changed the service name to default then i deploy with the default service the cron job task path was pointed to the default path of app engine so that when the task was scheduled 404 error raised because the path doesn't match when the service name set to "environ-flexible"
In app.yaml
change :
service: environ-flexible
to
service: default