Freedns or noip setup for NextCloudPi not working

My RaspberryPi 3b is running the latest NextCloudPi image.

Inside my local network everything works fine. When trying to access NextCloud from outside by setting up either freeDNS or no-ip I get the same curl error each time. Example for no-ip:

[ no-ip ] (Mon Oct 23 17:55:25 BST 2023)

Auto configuration for Linux client of

Only one host [<my-noip-domain>] is registered to this account.
It will be used.

New configuration file '/usr/local/etc/no-ip2.conf' created.

Failed to enable unit: Unit /run/systemd/generator.late/noip2.service is transient or generated.
System config value trusted_domains => 3 set to string <my-noip-domain>
System config value overwrite.cli.url set to string https://<my-noip-domain>/
System config value trusted_proxies => 11 set to string
System config value trusted_proxies => 12 set to string ::1
System config value trusted_proxies => 13 set to string <my-noip-domain>
System config value trusted_proxies => 14 set to string <my-ipv4>
Setup notify_push (attempt 1/5)
✓ redis is configured
🗴 can't connect to push server: cURL error 28: Connection timed out after 30001 milliseconds (see for https://<my-noip-domain>/push/test/cookie

I can’t do port-forwarding on my router, nor can does UPNP work. Is that a requirement?

Let me know if you need any further details regarding my setup.
Thanks in advance!

no-ip (and all dyndns services) resolv the external address of the router to the specified hostname. For access to an internal server you must allow port-forwarding.

all right, thanks. I had a misunderstanding about how these services work.