Sometimes php-fpm unexpectedly stopped, so the first thing to check is the status php-fpm, if it is down, the need to open.
systemctl status php-fpm
The best set about boot: systemctl enable php-fpm
Sometimes php-fpm unexpectedly stopped, so the first thing to check is the status php-fpm, if it is down, the need to open.
systemctl status php-fpm
The best set about boot: systemctl enable php-fpm