504 Gateway timeout error

Apologies if this is in the wrong forum, and if so can I request an admin to relocate it please.
I'm hosting a Woocommerce website on one of my CWP servers and part of the shop ordering process is that when the customer orders a meal they get a popup telling them that the restaurant will either accept or cancel their order. The message keeps refreshing whilst it is waiting for a response from the restaurant kitchen to click at their end to accept the order or not.
If this process takes a little longer than expected, the customer gets a 504 Gateway Timeout error and the popup dissappears leaving the customer unaware if their order is coming or not.
Am I right in thinking that somewhere I need to increase the wait time on the server in order to give this app more time. If so has anyone any idea where this would be.
I'm running PHP 7.3, nginx-varnish-apache. Apache version 2.4.39

hi you can increase the timeout directive it depends on the model
what php handler you're using php-cgi or php-fpm ?

Hi and thanks for the reply.
According to the API I'm running CGI

But I'm running forced PHP-FPM would that also be an issue?

kindly confirm what you're using and get back here. Check php info for domain not from cwp