Hello @Vsadygv, welcome to the Let's Encrypt community. 
Edit: we really have no clue about your system and its environment.
If you must redacted your domain name please see https://example.com/ as that is what example.com is for.
When you opened this thread in the Help section, you should have been provided with a questionnaire. Maybe you didn't get it somehow (which is weird), or you've decided to delete it. In any case, all the answers to this questionnaire are required:
Please fill out the fields below so we can help you better. Note: you must provide your domain name to get help. Domain names for issued certificates are all made public in Certificate Transparency logs (e.g. crt.sh | example.com), so withholding your domain name here does not increase secrecy, but only makes it harder for us to provide help.
My domain is: jellyfin.example.com
I ran this command: sudo certbot certonly --nginx -d jellyfin.example.com
It produced this output: the message the OP shared above
My web server is (include version): guessing nginx (but is it really, and what version)
The operating system my web server runs on is (include version):
My hosting provider, if applicable, is:
I can login to a root shell on my machine (yes or no, or I don't know): guessing yes
I'm using a control panel to manage my site (no, or provide the name and version of the control panel): guessing no
The version of my client is (e.g. output of certbot --version or certbot-auto --version if you're using Certbot): How did Certbot get installed on the system? certbot --version
Thank you for assisting us in helping YOU!