XF 2.2 Import RSS strange error


Active member
Hello! I need some advice how to debug this problem. After I switch server with same config for all stuff (servers was synchronized) xenforo RSS Import stopped working. Firstly I got 504 error like this:

2022/01/11 19:58:25 [error] 1435#1435: *1907657 upstream timed out (110: Connection timed out) while reading response header from upstream, client: x.x.x.x, server: mysite.ru, request: "POST /talk/admin.php?feeds/name.1/save HTTP/1.1", upstream: "fastcgi://", host: "mysite.ru", referrer: "https://mysite.ru/admin.php?feeds/name.1/edit"

So I've increased fastcgi_read_timeout , but nothing happens: if I try to preview feed, after few minutes loading indicator just stops with no error in xenforo error log, nginx log or php-fpm log.

How to debug this issue?