Send message in RDS to logoff

Import-Module RemoteDesktop
Import-Module RemoteDesktopServices

$primaryBroker = (Get-RDConnectionBrokerHighAvailability -ConnectionBroker Servername).ActiveManagementServer
$c = get-RDSessionCollection -ConnectionBroker $primaryBroker

$c| % {
    $coll = $_.CollectionName

    write-host "Active users in $($_.CollectionName)" -ForegroundColor Cyan
    Get-RDUserSession -ConnectionBroker $primaryBroker -CollectionName $_.collectionName | ? sessionstate -EQ "State_active" |% {

    Write-Host $_.username
    Send-RDUserMessage -HostServer $_.HostServer -UnifiedSessionID $_.UnifiedSessionId  -MessageTitle "Message from Administrator" -MessageBody "Please save your work. You will be logged off in 5 minutes"

    }
}