Error 504

Hi,
i get "504 Gateway Timeout Error"  when i use google sitemap generator on prestashop
in Apache error log i have this :

Code: [Select]

...[proxy_fcgi:error] [pid 30676:tid 139657698305792] (70007)The timeout specified has expired: [client xx.xx.xxx.xx:xxxxx] AH01075: Error dispatching request to : (polling), referer: https://...
configuration Apache + nginx + php-fpm 7.2.14

so, i think that it is "proxy timeout" or something like this, but i can't find file or place to change this parameter .
need help