After updating my WordPress site I had to clear the cache. I’m using Nginx’s Microcache and I really believed that I could flush it be restarting Nginx. However, that didn’t do the trick as I still kept seeing the old WordPress content. What you have to do is to clear the contents of the Nginx cache folder. This can be done by following these steps.

1. Find you cache path. It might be set in the variable fastcgi_cache_path. If not, the default seems to be /var/cache/nginx/
2. Remove the cache folder by executing the following command  rm -rf /var/cache/nginx/
3. Restart Nginx to reenable caching

https://www.sorendam.com/clear-nginx-cache/

https://ubiq.co/tech-blog/disable-nginx-cache/