Home Assistant OS can't get an ssl certificate

Good day! OS 6.4 Home Assistant can’t get an ssl certificate. Since this is the OS, it is impossible to change something like in docker! Has anyone ever encountered such a problem? In the topics, I did not find information on such a problem on HA OS or was inattentive! Please help or give a link to a topic with a similar problem! Thanks!

log
[10:58:12] INFO: Selected http verification
Saving debug log to /var/log/letsencrypt/letsencrypt.log
Plugins selected: Authenticator standalone, Installer None
Obtaining a new certificate
Performing the following challenges:
http-01 challenge for mydomain.duckdns.org
Waiting for verification...
Challenge failed for domain mydomain.duckdns.org
http-01 challenge for mydomain.duckdns.org
Cleaning up challenges
Some challenges have failed.
IMPORTANT NOTES:
 - The following errors were reported by the server:
   Domain: mydomain.duckdns.org
   Type:   connection
   Detail: Fetching
   http://mydomain.duckdns.org/.well-known/acme-challenge/k8IXbxxxxxk2xxxxXHS6XnPq8CYkZt-NyKT2yE6N_Ga8zoQg:
   Timeout during connect (likely firewall problem)
   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. Additionally, please check that
   your computer has a publicly routable IP address and that no
   firewalls are preventing the server from communicating with the
   client. If you're using the webroot plugin, you should also verify
   that you are serving files from the webroot path you provided.
[cont-finish.d] executing container finish scripts...
[cont-finish.d] done.
[s6-finish] waiting for services.
[s6-finish] sending all processes the TERM signal.
[s6-finish] sending all processes the KILL signal and exiting.

seems your domain isn’t reachable

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. Additionally, please check that
   your computer has a publicly routable IP address and that no
   firewalls are preventing the server from communicating with the
   client

have you acces to your hassio from the net with your fqdn ?