CNAME to duckdns stopped working

Hi,

Let's say my domain is aaa.net

About a year or so ago I set up a cname to point to my duckdns.org domain.

All worked fine. Today, it stopped working.
Looking at the panel, all seems right.

What I did and was working is:
- I created a CNAME record with name "tree" to point to "xxx.duckdns.org"

- When using http://tree.aaa.net it was working until today.
- When using http://xxx.duckdns.org it worked before and is still working.

I deleted and recreated the cname record to no avail.

It does not work from the browser and if I do dig or nslookup, it does not find it either.

What could be happening?

Thanks in advance!

another CNAME stopped working too.

WWW is pointing to github pages and if I use the github pages address it works but if I use https://www.aaa.net it does not.