Localhost Nginx raise no-referrer-when-downgrade in browser - http

Question

I have HTTP cloud functions running locally and i want to hide them behind a reverse proxy to reproduce the same architecture i have in production.
When i call directly the endpoint, it's fine. But when i use my react application, it's not working. I don't manage to fix the issue.
Can you help me please?
Nginx conf :
server {
listen 9003;
#add_header 'Referrer-Policy' 'no-referrer';
add_header 'Referrer-Policy' 'unsafe-url';
location /api/callImportEvent/ {
add_header 'Referrer-Policy' 'unsafe-url';
if ($request_method = OPTIONS ) {
add_header "Access-Control-Allow-Origin" *;
add_header "Access-Control-Allow-Methods" "GET, POST, OPTIONS, HEAD";
add_header "Access-Control-Allow-Headers" "Authorization, Origin, X-Requested-With, Content-Type, Accept";
return 200;
}
proxy_pass http://192.168.99.1:8888/;
proxy_redirect off;
proxy_pass_header Authorization;
proxy_pass_header x-api-key;
proxy_set_header X-Real-IP $remote_addr;
proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
}
}
Cloud function command : 
$(gcloud beta emulators pubsub env-init) && functions-framework --target=callImportEventHttp --signature-type=http --source=./index.js --port=8888
Direct curl (working) :
rbarbu#DESKTOP-7EQNOFM:~$ curl -v 'http://localhost:9003/api/callImport/'
* Trying 127.0.0.1...
* TCP_NODELAY set
* Connected to localhost (127.0.0.1) port 9003 (#0)
> GET /api/callImport/ HTTP/1.1
> Host: localhost:9003
> User-Agent: curl/7.58.0
> Accept: */*
>
< HTTP/1.1 456 unknown
< Server: nginx/1.14.0 (Ubuntu)
< Date: Mon, 07 Sep 2020 15:37:16 GMT
< Content-Type: application/json; charset=utf-8
< Content-Length: 61
< Connection: keep-alive
< X-Powered-By: Express
< ETag: W/"3d-kbNXdE/Nx2cqqnUsIdQHlgSM74w"
<
* Connection #0 to host localhost left intact
{"status":"Unrecoverable Error","message":"No API KEY given"}r
Call from React APP (not Working):
Direct call to NGINX URL from Browser (working):