Currently, due to some limitations with how appointments are created and sent in outlook, when sending out an appointment, the invitee will receive it from User, however the version that the user receives is from crmemails.
This sets crmemails as the organizer, and means that the user is unable to make any amendments to the appointments, as they are not the organizer. Previously it would send an appointment to the user, but as they were already set as the organizer, outlook would not allow them to add it to their calendar, but it would not already be there, so they would not be able to accept this invitation.
We should review this to see if there is a way to be able to send appointments through the CRM, with the invite to the user also setting them as the organizer when they accept it.