Can't get a SSL certificate

[ivanprea]

Hello,
I was watching a video to how t setup duckdns and nginx to have a ssl certificate so a https (on CASAOS). But once i put my dns domain i got this error: CommandError: Saving debug log to /tmp/letsencrypt-log/letsencrypt.log
Some challenges have failed.
Ask for help or search for solutions at https://community.letsencrypt.org/. See the logfile /tmp/letsencrypt-log/letsencrypt.log or re-run Certbot with -v for more details.

at /app/lib/utils.js:16:13
at ChildProcess.exithandler (node:child_process:430:5)
at ChildProcess.emit (node:events:519:28)
at maybeClose (node:internal/child_process:1105:16)
at ChildProcess._handle.onexit (node:internal/child_process:305:5)

I don't know anything about this stuff honestly. I tried out of curiosity but i can't pass this step. Can someone help me?