sudo nano /etc/nginx/sites-available/default

Меняем содержимое на:
!!!Меняем путь в root


server{
 charset utf-8;
 client_max_body_size 128M;

 listen 80;

 server_name backend.dev;
 #root /var/www/yii/project/backend/web;
 root /var/www/yii/crm_2.3/frontend/web;
 #root /var/www/yii/crm_2.3/backend/web;
 index index.php;

 access_log /var/log/nginx/access.log;
 error_log /var/log/nginx/error.log;

 location / {
 try_files $uri $uri/ /index.php?$args;
}

 include /etc/nginx/php.conf;

 location ~* .(jpg|jpeg|gif|png|css|js|ico|xml)$ {
 access_log off;
 log_not_found off;
 expires off;
}

 location ~ /.(ht|svn|git) {
 access_log off;
 log_not_found off;
 deny all;
 }
}


Создаем файл /etc/nginx/php.conf:
sudo touch /etc/nginx/php.conf

Добавляем в него содержимое:

sudo nano/etc/nginx/php.conf


location ~ .php$ {
 include fastcgi_params;
 #fastcgi_pass 127.0.0.1:9000;
 fastcgi_pass unix:/run/php/php7.0-fpm.sock;
 #fastcgi_pass unix:/run/php5-fpm.sock;
 fastcgi_read_timeout 3000;


 fastcgi_param  SCRIPT_FILENAME $document_root$fastcgi_script_name;
 fastcgi_buffers 16 16k;
 fastcgi_buffer_size 32k;
}