After updating the Synology and switch webserver from Apache to Nginx, the web-based RSS reader selfoss stopped working. This application uses a .htaccess file to rewrite all requests in Apache. Unfortunately, Nginx doesn’t support .htaccess files.
Make these adjustments in: /etc/nginx/app.d/server.webstation-vhost.conf (last line before the final closing bracket ‘}’. Keep in mind, the space after $1 belongs in the configuration file. If you forget about this nginx won’t restart (with the command: nginx -s reload).

# Custom configuration by Randy - Fix SelfOss RSS reader
location /selfoss {
 root /volume1/web;
}
location ~ ^/selfoss/$ {
 index index.php;
}
location ~ ^/selfoss/favicons/(.+)$ {
 try_files /selfoss/data/favicons/$1 =404;
}
location ~ ^/selfoss/(.+)$ {
 try_files /selfoss/public/$1 /selfoss/index.php$is_args$args;
}

If you also want to switch other applications from Apache reverse proxy to Nginx, the configuration would be:

# Custom configuration by Randy - Add reverse proxies
location /sabnzbd {
  proxy_pass http://127.0.0.1:8080;
}
location /sb {
  proxy_pass http://127.0.0.1:8083/sb;
}
location /transmission {
  proxy_pass http://127.0.0.1:9091/transmission;
}
location /couchpotato {
  proxy_pass http://127.0.0.1:5053/couchpotato;
}
# Spotweb fix for API via NGingx
location /spotweb {
 if ($uri !~ "api/"){
 rewrite api/?$ /spotweb/index.php?page=newznabapi last;
 }
}