I move the Channel Manager group under "Manager" group and it works now.
Previously, it doesn't work because new moderator group doesn't have administrator permission.
Alternatively, if I don't want to add Moderator to Manager group, give the administrative permissions (Allowed Access Administration Interface, Create, Delete, Edit, Edit State) to moderator group and assign the moderator to user group of user who I want to edit. It works too.
Thank.