I have Ubuntu 18.04, Nginx VPN running 4 wordpress sites (https enabled). These sites uses Cloudflare plugin. When I published new posts or purge cloudflare cache by using WordPress plugin it gives following error.
PHP message: [Cloudflare] ERROR: Bad Request" while reading response header >from upstream, client
In my Nginx configuration, I have increased the fastcgi_buffer_size to 32k.
fastcgi_buffer_size 32k;
Moreover, I have increased following nginx header related optimizations to handle large headers,
client_header_buffer_size 64k;
http2_max_header_size 32k;
large_client_header_buffers 4 64k;
proxy_buffer_size 256k;
proxy_buffers 8 256k;
proxy_busy_buffers_size 512k;
But still I'm getting this error. How do I determine up to which level should I increase these things? Or are there any other better way to fix this error?
This is the full error log: - https://pastebin.com/aPfZ5V7a
