+ increase proxy buffers for headers from proxy upstream & increase client header buffers

config/nginx/conf.d/vhosts.conf.example

@@ -35,6 +35,10 @@ server {
     include includes.d/octobercms.conf;
     include includes.d/staticfiles.conf;
     client_max_body_size 300M;
+    large_client_header_buffers 4 32k;
+    proxy_buffer_size 16k;
+    proxy_buffers 8 16k;
+    proxy_busy_buffers_size 32k;
     location ~ ^/index.php {
         fastcgi_pass php81;
         include fastcgi_params;