Invalid CORS request error on NiFi v1.8.0 and 1.9.0 behind nginx

[Elemir Stevko]

Hello,

I have been running a single instance of NiFi server v1.7.1 on AWS behind ALB 
and nginx:

ALB -> nginx -> NiFi

The configuration has been working fine, but since NiFi v1.8.0, I get Invalid 
CORS request error when I try uploading a template file. Is there anything I 
need to change in the proxy configuration as compared to NiFi v1.7.1?

Here are more details on the NiFi configuration:

- ALB terminates the HTTPS connection and opens a new HTTPS connection to nginx 
which then proxies the request to NiFi server.

- NiFi server is configured with OIDC authentication. Neither ALB nor nginx 
authenticate the clients, they just proxy the requests to NiFi.

- nginx is configured similarly to Koji's repo ijokarumawak/nifi-reverseproxy 
(nginx/standalone-plain-http/nginx.conf):

server_names_hash_bucket_size 128;

upstream localhost {
  server localhost:9443;
}

server {
  listen              443 ssl;
  server_name         _;
  ssl_certificate     /usr/local/etc/ssl/public.pem;
  ssl_certificate_key /usr/local/etc/ssl/private.key;
  ssl_protocols       TLSv1 TLSv1.1 TLSv1.2;
  ssl_ciphers         HIGH:!aNULL:!MD5;

  proxy_ssl_trusted_certificate /opt/nifi/cert/nifi-cert.pem;

  access_log /var/log/nginx/nifi.access.log combined;

  location / {
    proxy_pass https://localhost;
    proxy_set_header X-ProxyScheme https;
    proxy_set_header X-ProxyHost $host;
    proxy_set_header X-ProxyPort 443;
    proxy_set_header X-ProxyContextPath /;
  }
}

Best regards,
Elemir