Unable to put nodes in maintenance mode with SDK since upgrading

I now get an error from the power shell script i got from the sdk github page. Here is the error i'm getting.

Get-SwisData : An error occurred when verifying security for the message.

At line:19 char:13

+     $uris = Get-SwisData $swis $strQuery

+             ~~~~~~~~~~~~~~~~~~~~~~~~~~~~

    + CategoryInfo          : InvalidOperation: (:) [Get-SwisData], MessageSecurityException

    + FullyQualifiedErrorId : SwisError,SwisPowerShell.GetSwisData

here is line 18 and 19

    [String]$strQuery = "SELECT uri FROM Orion.Nodes WHERE SysName LIKE '" + "$server" + "%'" 

    $uris = Get-SwisData $swis $strQuery

Does anyone have any idea why i'm getting this since upgrading to Orion Platform 2018.4 HF1. Here is the full script

#Region PSSnapin presence check/add 

if (!(Get-PSSnapin -Name "SwisSnapin" -ErrorAction SilentlyContinue)) 

{     

    Add-PSSnapin SwisSnapin -ErrorAction SilentlyContinue 

} 

#EndRegion 

$serverlist = Get-Content -Path "C:\Temp\unmanageservers.txt" 

$username = "user"

$password = "password"

$secstr = New-Object -TypeName System.Security.SecureString

$password.ToCharArray() | ForEach-Object {$secstr.AppendChar($_)}

$cred = new-object -typename System.Management.Automation.PSCredential -argumentlist $username,$secstr

$strOrionServer="solarwinds" 

$swis = Connect-Swis -Hostname $strOrionServer -Credential $cred

foreach($server in $serverlist){ 

    [String]$strQuery = "SELECT uri FROM Orion.Nodes WHERE SysName LIKE '" + "$server" + "%'" 

    $uris = Get-SwisData $swis $strQuery

    $uris | ForEach-Object { Set-SwisObject $swis $_ @{Status=9;Unmanaged=$true;UnmanageFrom=[DateTime]::UtcNow;UnmanageUntil=[DateTime]::UtcNow.AddHours(2)}}  

}