Hello,
at the moment it is not possible to response external in tickets or make an internal comment.
Also we cannot give a ticket to another group member.
If we try we get the following message: " OOPS Diese App hat das Einreichen des Tickets verhindert. Bitte wenden Sue sich an den Zendesk-Administrator, der diese App installiert hat, um weitere Informationen zu erhalten."
The mentioned administrator does not exist anymore. And so no one has additional information about the issue.