Make sure that your Synology device is configured to answer for www.hotel-lc.online as well as hotel-lc.online.
Alternatively, you can redirect from www to your domain as here…
Note that port 443 is not open on your device so you are using Cloudflare SSL/TLS “Flexible” mode and therefore your connection between Cloudflare and your server is not secured. You should make sure your Synology webserver is configured to support SSL with a valid SSL certificate on that end, and set Cloudflare’s SSL/TLS to “Full (strict)”.