If ubuntu is not a user added to Hestia, then you won’t see any domains because your domains have been added to other user (or users). You must login via ssh with the user assigned to your domains. By default you will only be able to login using sftp but not ssh, to login using ssh add a shell to the user:
v-change-user-shell YourUser bash
Or via Web UI, login as admin → edit the user you want to modify → advanced options → on SSH access, change nologin to bash and Save.