Error 504 Gateway Time out

Hi Matteo-
From what you’ve described, the timeout is occurring whenever the cache is automatically purged.
The first thing to check is your debug log. Add the following lines to your wp-config.php file:

define( 'WP_DEBUG', true ); 
define( 'WP_DEBUG_LOG', true ); 
define( 'WP_DEBUG_DISPLAY', false );

Once you have that, enable the plugin and update a post to recreate the error. Now, you’ll have a log of any errors in wp-content/debug.log . Let us know what errors you see there and we can do some more digging.

I also noticed you’re using an NGINX proxy. If you have root access to your server, I recommend setting a few of the NGINX configurations in /etc/nginx/conf.d/timeout.conf:

proxy_connect_timeout 600; 
proxy_send_timeout 600; 
proxy_read_timeout 600; 
send_timeout 600;

In addition, I’d recommend setting your PHP execution time in php.ini.

max_execution_time 300

Once you’ve made all those changes, restart NGINX and see if the error persists.

Hi Matteo-
If WordPress isn’t throwing any errors, then I’d suspect the timeout values in NGINX or PHP are too low. Did you get a chance to check those?