The .org domains were discontinued for regular users back in 2021. We were forced to move users to a different domain because users kept getting their account hacked or setting up abuse (like phishing sites) and getting the main heliohost.org website blacklisted on places like Facebook.
Users that had them prior to that date were allowed to keep them until they were removed from the account (which in the case of the Johnny crash, everyone on Johnny had their domains removed). The helioho.st and heliohost.us domains are the replacements.
If you need it back temporarily, it can be added as an alias that redirects to your new domain, however, there will be a time when they stop working entirely for users. Do you want me to do that?