Failure during email generation

[CTDhelpdesk]

Using the latest revision of the script, I get this error when it gets to the point of actually creating / sending the email:

C:\Scripts\Backend\ChangeHistory\example.org_Administrators-ChangeHistory.csv
VERBOSE: [Monitor-ADGroupMemberShip.ps1][Process] Administrators - Change History Process Completed
VERBOSE: [Monitor-ADGroupMemberShip.ps1][Process] Administrators - Save Changes to a ChangesHistory File
VERBOSE: [Monitor-ADGroupMemberShip.ps1][Process] Administrators - Preparing the notification email...
WARNING: [Monitor-ADGroupMemberShip.ps1][Process] Something went wrong
WARNING: Object reference not set to an instance of an object.
VERBOSE: [Monitor-ADGroupMemberShip.ps1][Process] Group: CSAdministrator...
VERBOSE: [Monitor-ADGroupMemberShip.ps1][Process] Active Directory Module
VERBOSE: [Monitor-ADGroupMemberShip.ps1][Process] Extracting Domain Name from example.org/Users/CSAdministrator
VERBOSE: [Monitor-ADGroupMemberShip.ps1][Process] Group: CSAdministrator - Querying Membership (AD Module)
VERBOSE: [Monitor-ADGroupMemberShip.ps1][Process] CSAdministrator - The following file exists: example.org_CSAdministrator-membership.csv
VERBOSE: [Monitor-ADGroupMemberShip.ps1][Process] CSAdministrator - Comparing Current and Before
VERBOSE: [Monitor-ADGroupMemberShip.ps1][Process] CSAdministrator - Compare Block Done!
VERBOSE: [Monitor-ADGroupMemberShip.ps1][Process] CSAdministrator - No Change
VERBOSE: [Monitor-ADGroupMemberShip.ps1][End] Script Completed

Not sure what Object Reference not set to an instance of an object means...

Love the script though, thanks for all your hard work!