I followed this tutorial to set up local domain names with SSL-certificates using DuckDNS: notthebe.ee/blog/easy-ssl-in-homelab-dns01/

I have three local domains for my Nginx Proxy Manager running on a VPS, for my self-hosted Nextcloud and my Proxmox-WebGUI both running on my local Homeserver. They follow the scheme service.dataprolet.duckdns.org.

Now I use Uptime-Kuma to monitor my services including the three domains and for some reason those three domains constantly time out after 48 seconds. I already set up the retries to 3, but to no avail.

I also use Pi-hole and Unbound and thought, that might be an issue, but testing my DNS using dig, mtr, traceroute, nslookup and host all returned normal values and no errors.

Does anybody have any idea what could cause this? I’m kind of clueless at this point. Thanks in advance!