Hello,
there is an error in the installer under ubuntu 22.04. the domain “.example.com” was added to the hostname. check the installer file: https://raw.githubusercontent.com/hestiacp/hestiacp/release/install/hst-install-ubuntu.sh
Make sur to provide a valid hostname sub.domain.com and it should never been added…
it is possible that the dns data has not yet been updated.