my problem is, that it's impossible to create a ssl certificate. That's strange because this is my second server (same brand, type, os and so on). On the first one all is okay. And now I have no clue what's going wrong.
Obtaining a new certificate
Performing the following challenges:
http-01 challenge for node02.ironpvp.de
Waiting for verification...
Challenge failed for domain node02.ironpvp.de
http-01 challenge for node02.ironpvp.de
Cleaning up challenges
Some challenges have failed.
To fix these errors, please make sure that your domain name was
entered correctly and the DNS A/AAAA record(s) for that domain
contain(s) the right IP address.
My web server is (include version) / The operating system my web server runs on is (include version):
Ubuntu 20.04 LTS
NGINX: 1.20.1
I can login to a root shell on my machine (yes or no, or I don't know): yes
I'm using a control panel to manage my site (no, or provide the name and version of the control panel): no
The version of my client is (e.g. output of or certbot-auto --version if you're using Certbot): 0.40.0
There are some nginx distributions out there which have "security" modules that create JavaScript interstitials, sort of like the Cloudflare captcha page. They look a lot like that snippet.
If that's the case here, @Cycs will need to figure out where it's coming from and turn it off, or exclude these requests.
Select the appropriate numbers separated by commas and/or spaces, or leave input
blank to select all options shown (Enter 'c' to cancel):
Requesting a certificate for node02.ironpvp.de
Hint: The Certificate Authority failed to verify the temporary nginx configuration changes made by Certbot. Ensure the listed domains point to this nginx server and that it is accessible from the internet.
Some challenges have failed.
Ask for help or search for solutions at https://community.letsencrypt.org. See the logfile /var/log/letsencrypt/letsencrypt.log or re-run Certbot with -v for more details.
So ... it will not work.
Btw. you asked for the strange text ... I only copied the output from the shell.
Uh ... sorry. I do not know.
I only installed the server from scratch. That means, I clicked on "install server with Ubuntu 20.04 LTS" on my providers panel. After that I installed NGINX in this way:
The clue is that @9peppe's curl response does not contain the Server header. This is usually a dead giveaway that there's some kind of proxy sitting in front.
I'd contact your host. I think it's some kind of HTTP firewall on their side.