CNAME for own domain

Hello together,
I hope, I choose the right category here.

I set up my own webserver and wanted to make it reachable with my own domain, so I created a dynamic dns-domain (which works fine) and set a CNAME-Entry for which leads to The main-domain is forwarded (alias) to
However this doesnt work. I’m new in these things and I hope that I just forgot something or made a simple mistake. I’m grateful for every hint. Thank you very much!

It looks good so far and it seems to work. Maybe you just needed to wait, because DNS entries have a time to live and cached entries need to expire.

Thank you for your answer, corny!
You’re right, it works now. The main problem was, I had no SSL-Certificate. Now I got one with let’s encrypt / certbot.
Instead of telling me, this website is not sure (which I would expect), firefox told me, the connection failed. I’m still wondering, why I was able to reach the website via the dyndns-domain before I installed the SSL-Certificate.

Edit: How can I mark this problem as solved?

The reponse for could have been cached with a longer time to live (TTL). That’s why your it took longer to reach your server using this domain.

Topic can not be marked as solved yet. This will come in the future.

Yes, sometimes I’m a little impatient…
Thank you very much, corny, you’re doing great work here!