Pasted

location /blog/ {
  proxy_set_header  Host               $host;
  proxy_set_header  X-Real-IP          $remote_addr;
  proxy_set_header  X-Forwarded-For    $proxy_add_x_forwarded_for;
  proxy_set_header  X-Forwarded-Proto  $scheme;
  proxy_pass http://wordpress/; # <-- mind the trailing slash!
}