The Administrators of your organization in Ommnio (Communication, Human Resources, or General Management personnel) can create and delete groups, as well as subscribe or unsubscribe users.
Perhaps the group has been deleted, or maybe you have been unsubscribed from it. In any case, don't worry because it's not something you have done.
If you believe you should be part of this group, read this article 👉 Can I join a group?