Solved adding this on nginx configuration:

location /phpmyadmin {
  root /usr/share/;
  index index.php;
  try_files $uri $uri/ =404;

  location ~ ^/phpmyadmin/(doc|sql|setup)/ {
    deny all;
  }

  location ~ /phpmyadmin/(.+\.php)$ {
    fastcgi_pass unix:/run/php/php7.0-fpm.sock;
    fastcgi_param SCRIPT_FILENAME $document_root$fastcgi_script_name;
    include fastcgi_params;
    include snippets/fastcgi-php.conf;
  }
 }