But it doesn’t work. I’m frustrated.
I have done the steps for trusting root CA for Linux. After that it said “1 added”. So it seemed to have worked.
I have tried to do the final steps for Brave and Firefox but in both cases the menu is completely different to the description. It seems to be outdated.
In the case of Brave I managed to add the certificate as trusted, anyway.
But still there is no connection.
When you direct Firefox to your server’s unique adjective-noun.local address, what message do you receive?
It says:
Hmm. We’re having trouble finding that site.
We can’t connect to the server at -.local.
If you entered the right address, you can:
Try again later
Check your network connection
Check that Firefox has permission to access the web (you might be connected but behind a firewall)
Are you able to connect to your server from another device?
Yes I can connect to it from a Windows PC.
Great. You can find the IPV4 address under System>About.
Try the IP address in Firefox, on Ubuntu. This will tell us a lot about what’s going on.
No. Your server has only one root certificate authority. But it does need to be imported to each device which will connect to your server. I believe you’ve already done so, based on your OP.
This tells us two things. You are having an mDNS resolution problem, and the Firefox setup has not been completed. Probably best to focus on the mDNS issue first. What version of Ubuntu are you on?
Please open a terminal, and ping your server using your unique adjective-noun.local address.
ping adjective-noun.local
Yes it couldn’t complete setup in firefox but in brave. because the menu is very different to the describtion.
Ubuntu 24.04.3 LTS
Ping: Name or Service not known
Please provide the output of the following terminal command:
systemctl is-active avahi-daemon
Restart the Ubuntu computer, and then provide the output of same the command again.
Output is: active
Before and after restart.
The good news is, the server appears to be working fine. We’ve reached a dead-end, for this logical maze. Please review the steps we’ve tried, and the information you’ve provided. Something may be missing, or incorrect. A typo in the adjective-noun.local address? Otherwise, your avahi daemon is broken, even though it shows active. That’s where you’ll need to focus your efforts. You may find it easiest to just restore your Ubuntu system, as my understanding is that it should work out of the box. Maybe someone else will come along that thinks of something I have missed.
I reviewed the steps and at the firefox windows (where I send a screenshot from) I just clicked “SKIP (not recommended)” then I was able to log in 
Eventhough I didn’t complete the steps for firefox.
Then I tried Brave Browser with the IP adress and it immediately showed something like “root certificate accepted” and I was able to log in.
Just worked with the IP. But not with my servers “adjective-noun” (no typo)
Your hint to use the IP adress helped at the end. Thank you 
That will allow you to administer your server, but ultimately you’ll need avahi working correctly in order for Ubuntu to utilize services you have running on your server. They cannot be accessed via IP:port.
