Microsoft Exchange Set-Mailbox Befehl wird falsch verabeitet

# Setzen der Variablen für die OU und die Quoten in GB
$OU = "OU=YourOU,DC=yourdomain,DC=com"  
$IssueWarningQuota = 9.9
$ProhibitSendQuota = 10
$ProhibitSendReceiveQuota = 10.5

# Konvertierung in Byte-Werte
$IssueWarningQuotaBytes = [long]($IssueWarningQuota * 1024 * 1024 * 1024)
$ProhibitSendQuotaBytes = [long]($ProhibitSendQuota * 1024 * 1024 * 1024)
$ProhibitSendReceiveQuotaBytes = [long]($ProhibitSendReceiveQuota * 1024 * 1024 * 1024)

# Ausgabe zur Überprüfung
Write-Output "IssueWarningQuotaBytes: $IssueWarningQuotaBytes"  
Write-Output "ProhibitSendQuotaBytes: $ProhibitSendQuotaBytes"  
Write-Output "ProhibitSendReceiveQuotaBytes: $ProhibitSendReceiveQuotaBytes"  

# Importieren des Exchange-Moduls (falls notwendig)
# Import-Module ExchangeOnlineManagement

# Verbinden zu Exchange Online (Falls Exchange Online verwendet wird)
# Connect-ExchangeOnline -UserPrincipalName <admin_user>@yourdomain.com -ShowProgress $true

# Holen der Postfächer in der angegebenen OU
$Mailboxes = Get-Mailbox -OrganizationalUnit $OU

foreach ($Mailbox in $Mailboxes) {
    Set-Mailbox -Identity $Mailbox.samAccountName -UseDatabaseQuotaDefaults $false -IssueWarningQuota $IssueWarningQuotaBytes -ProhibitSendQuota $ProhibitSendQuotaBytes -ProhibitSendReceiveQuota $ProhibitSendReceiveQuotaBytes
}

# Trennen von der Exchange Online Sitzung (Falls Exchange Online verwendet wurde)
# Disconnect-ExchangeOnline -Confirm:$false