Python 3.x/Flask – Using Cloudwatch handler throws CORS error when login in

I’m working on a project that uses flask w/ python 3.10 and react.
Everything works fine, but the logs were a local file and we decided to move it to Cloudwatch.
Wrote the code, changed the loguru sink, everything seemed ok, It works locally!
When we deploy the application, we get a CORS error on the react application, can’t even login anymore. Removing the cloudwatch handler from the loguru sink makes everything works smoothly again.
The frontend doesn’t log anything to cloudwatch or the backend and I really can’t understand what’s going on here.

The exact error on console is:

Access to XMLHttpRequest at 'my.ip:port/login' from origin 'my.ip' has been blocker by CORS policy
: Response to preflight request didn`t pass access control check: No 'Access-Control-Allow-Origin' header is present on the requested resource.

My code is the following:

### Loguru config ###
from cloudwatch import cloudwatch
from loguru import logger
...
handler = cloudwatch.CloudWatchHandler( log_group = 'my_log_group', access_id='my_access_id', access_key='my_access_key')
logger.add(sink=handler, level='INFO')

### App config ###
from flask import Flask
from flask_cors import CORS
...
app: Flask = create_app()
api = Api(app)

#original config
cors = CORS(app, resources='*', headers='Content-Type')

# Tried like this, since resources by default should be *
# cors = CORS(app, supports_credentials=True)
# app.config['CORS-HEADERS'] = 'Content-Type'

# And like this
# cors = CORS(app, resources='*', headers='Content-Type', supports_credentials=True, send_wildcard=True)
# app.config['CORS-HEADERS'] = 'Content-Type'

Any help is much appreciated