So, something trouble if setting charset to utf-8 for nginx.
Copy /opt/configs/nginx/etc/conf/nginx.conf to custom.nginx.conf and then change:
from:
include koi-utf;
charset utf-8;
source_charset koi8-r;
to:
#include koi-utf;
#charset utf-8;
#source_charset koi8-r;
The same way to /etc/nginx/nginx.conf