I got both the Apache and Nginx servers working fine until I ran:
sudo certbot --nginx -d myhost.com -d www.myhost.com
and restarted Nginx.
Looking at the logs I get the error:
nginx: [crit] pread() "/etc/nginx/sites-enabled/mod_rpaf-stable" failed (21: Is a directory)
Is it a permissions issue like www-data or a problem with mod_rpaf-stable? I tried to find information online but I'm getting nowhere.