M365 Mails mit bestimmten Betreff und älter als 72h in allen Postfächern löschen

<#
    Remove messages older than x days with subject that contains specific subject string from all users mailboxes inbox folder
#>

# Variables ----------------------------------------------------
# tenant domain
$tenant = 'xxxxxxxx.onmicrosoft.com'  
# client id
$client_id = 'xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx'  
# client secret
$client_password = 'xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx'  
# subject substring to match
$subject_string = 'my subject to match'  
# only messages older than x days
$date = (get-date).AddDays(-3).Date
# --------------------------------------------------------------
$ErrorActionPreference = 'Stop'  
# needed modules
$modules = 'Microsoft.Graph.Mail','Microsoft.Graph.Users'  
# install modules if needed
$modules | %{
    if(!(Get-Module -ListAvailable -Name $_)){
        Install-Module $_ -Force -Scope CurrentUser
    }
    Import-Module $_
}

# connect to MG Graph
Connect-MgGraph -Tenant $tenant -ClientSecretCredential (new-Object PSCredential($client_id,(ConvertTo-SecureString $client_password -AsPlainText -Force))) -NoWelcome

# process each users mailbox
foreach($user in Get-MGUser -All -Property Id,Mail){
    # get messages with specific subject and older than x days from the inbox
    foreach ($message in Get-MgUserMailFolderMessage -MailFolderId inbox -UserId $user.id -All -Property id,subject,ReceivedDateTime -Filter "contains(subject,'$subject_string') and ReceivedDateTime lt $($date.toString('s'))Z"){  
        try{
            write-host "Removing message with subject '$($message.subject)' received on '$($message.ReceivedDateTime)' from mailbox '$($user.Mail)' ..." -F Green  
            Remove-MgUserMessage -MessageId $message.id -UserId $user.id
        }catch{
            write-host "Exception: $($_.Exception.Message)" -F Red  
        }
    }
}
# disconnect MG Graph session
Disconnect-MgGraph | out-null

foreach ($message in Get-MgUserMessage -UserId $user.id -All -Property id,subject,ReceivedDateTime -Filter "contains(subject,'$subject_string') and ReceivedDateTime lt $($date.toString('s'))Z"){