I fixed this by adding the following to: /etc/apache2/apache2.conf around line 20, just above the <IfModule mpm_prefork_module> block.
ServerName host.mydomain.com
(This should be ra.domain.com in your case.)
Update in /etc/apt/sources.list.d/hestia.list to use jammy instead of focal
(This issue has been discussed before in the forum, you can search for it.)