What's the net::ERR_HTTP2_PROTOCOL_ERROR about?

php wordpress google-chrome curl http2

PHP Snippet 1:

 server {
  ...
  ...
  gzip off;
  proxy_max_temp_file_size 0;
  location / {
    proxy_pass http://127.0.0.1:3000/;
  ....

PHP Snippet 2:

location /uploads {
    ...
    client_max_body_size 100M;
}

PHP Snippet 3:

{
 'Authorization': Authorization  //Authorization can't use null or ''
}

PHP Snippet 4:

JsonConvert.SerializeObject(myObject, new JsonSerializerSettings { ReferenceLoopHandling = ReferenceLoopHandling.Ignore })

PHP Snippet 5:

 http2 error: Invalid HTTP header field was received: frame type: 1, stream: 1, name: [content-security-policy], value: [script-src 'unsafe-inline' 'self....