Object reference not set to an instance of an object. [13-Mon]

Windows Server 2012 R2 - error consistent with three other VMs but many other vms are working with the same script Remote RM enabled and able to ping the box from the PA Monitor Server

$alert_output = "" $Updates = "" $UpdateSession = "" $UpdateSearcher = "" $Updatesresult = "" $Count = "" $Update = "" $Title = "" $KB = "" $IsDownloaded = "" $updatehistory = "" $updatehistorycount = "" $fwAlert = 0 $systename = $mon.ComputerName $session = New-PSSession -ComputerName "$systename" $sesoutput = $session.Availability if($session.Availability -ne "Available") { $mon.FireActions = $true $mon.Details = "Cannot connect" } else { $systenamecheck = Invoke-Command { $systename = $env:computername Return $systename } -Session $session $osversion = Invoke-Command { $osversion = [System.Environment]::OSVersion.Version Return $osversion } -Session $session
$Updatescount = Invoke-Command { $UpdateSession = New-Object -ComObject Microsoft.Update.Session $UpdateSearcher = $UpdateSession.CreateupdateSearcher() $Updates = @($UpdateSearcher.Search("IsHidden=0 and IsInstalled=0").Updates) $Updatesresult = $Updates | Select-Object -Property Title | out-string; $Updatescount = $Updates.count Return $Updatescount } -Session $session

if($Updatescount -gt 0)
{
    $fwAlert = 1
    $pending_output = Invoke-Command {
            $alert_output = ""
            $systename = $env:computername
                            $UpdateSession = New-Object -ComObject Microsoft.Update.Session
            $UpdateSearcher = $UpdateSession.CreateupdateSearcher()
            $Updates = @($UpdateSearcher.Search("IsHidden=0 and IsInstalled=0").Updates)
            $Updatesresult = $Updates | Select-Object -Property Title | out-string;
            $Updatescount = $Updates.count
            For ($i=0; $i -lt $Updatescount; $i++) 
            {
                $Update  = $Updates.Item($i)
                $Title =  $Update.Title
                $KB =  $Update.KBArticleIDs
                $MsrcSeverity = $Update.MsrcSeverity
                $IsDownloaded = $Update.IsDownloaded
                $Categories =  ($Update.Categories  | Select-Object  -ExpandProperty Name)
                $alert_output = $alert_output + "$i-$systename-$KB-$Categories-$Title-$IsDownloaded `n" 
            } 
    Return $alert_output                    
    } -Session $session
    $history_output = Invoke-Command {
        $alert_output = "`nUpdate History (Last 90 days) `n" 
        $updatehistory =  Get-HotFix | Where-Object {$_.InstalledOn -gt ((Get-Date).AddDays(-90))} |Sort-Object -Property @{Expression = "InstalledOn"; Descending = $True} 
        For ($j=0; $j -lt $updatehistory.count; $j++) 
        {
            $uh  = $updatehistory[$j]
            $Title =  $uh.Title
            $installedon = $uh.InstalledOn 
            $HotFixID = $uh.HotFixID
            $Description = $uh.Description
            $alert_output = $alert_output + "Date: " + $installedon + "   Description: " + $Description + "   HotFixID: " + $HotFixID + "`n"
        }
    Return $alert_output                    
    } -Session $session

}
else
{
    $fwAlert = 0
}

if($fwAlert -eq 1)
        {
            $mon.FireActions = $fwAlert 
            $mon.Details = "ALERT-$systenamecheck `n`r PENDING UPDATES $Updatescount`n`r$pending_output `n`r $history_output" 
        }
        else
        {
            $mon.FireActions = $fwAlert 
            $mon.Details = "Healthy-$systenamecheck-NO UPDATES $Updatescount "
        }

}