Only teachers explicitly allocated to a class can use the class group email address. Please submit a ticket to the TD Help Desk to change the allocation of teachers to classes in TD.
TD uses Google Groups to create class group email addresses. For example, the Year 2 Class at St Mary's Catholic Primary School North Sydney has the class group email address firstname.lastname@example.org. This is a Google Group with the two class teachers, joanne.frith and cath.pagett, set as owners of the group and the 34 students set as members of the group.
When Joanne or Cath email the email@example.com address the email will go to all 34 students and to the class teachers (i.e. each other).
However, the permissions on who can email this Google Group have been restricted by TD to the owner(s) of the group, that is, the class teacher(s). So, for example, students cannot email the class using this email address. Nor can other teachers who are not on this class. If students or other teachers not on this class try to email this group they will receive a "bounced" email message saying the email was not delivered (a "failed mail delivery notification").
This permission configuration is built-in to TD and cannot be changed.
If teachers at your school want to be able to use the class email addresses of other classes (i.e. they are not teachers of the class), then they must be allocated to the class. Please submit a ticket to the TD Help Desk to have this actioned. For secondary schools using Sentral, use the "Manage Roles" function to allocate teachers to classes, as per the instructions here.