Powershell Connect to SharePointOnline - list

Question

I developed a script to retrieve list items form a SharePoint Online server that works perfectly fine on my Windows 10 notebook, but not on a default Windows Server 2012 R2 instance. Here is the relevant code:
$context = New-Object Microsoft.SharePoint.Client.ClientContext($Url)
$context.RequestTimeout = 360000
$context.Credentials = New-Object Microsoft.SharePoint.Client.SharePointOnlineCredentials($UserName, $SecurePassword)
$list = $Context.Web.Lists.GetByTitle($ListTitle)
$qry = new-object Microsoft.SharePoint.Client.CamlQuery
$camlString = "somequery"
$qry.ViewXml = $camlString
$items = $list.GetItems($qry)
$Context.Load($items)
$Context.ExecuteQuery()
Unfortunately, the $list variable does not get any lists back from SharePoint on the 2k12 R2 server and therefore I get the following error in the end.
Exception calling "ExecuteQuery" with "0" argument(s): "Value cannot be null.
Parameter name: key"
At E:\temp\MDS_SharepointTracker_v2.ps1:131 char:5
+ $Context.ExecuteQuery()
+ ~~~~~~~~~~~~~~~~~~~~~~~
+ CategoryInfo : NotSpecified: (:) [], MethodInvocationException
+ FullyQualifiedErrorId : ArgumentNullException
I am pretty sure that it has something to do with the authentication, but I am not able to figure out what.
The credentials used for login are the same on both systems, both systems have the SharePoint Online Management Shell installed, Powershell version is the same and the DLLs loaded (see below). Proxy settings are the same on both systems. Through the browser, I can access SharePoint Online on the server.
[System.Reflection.Assembly]::LoadWithPartialName("Microsoft.SharePoint.Client")
[System.Reflection.Assembly]::LoadWithPartialName("Microsoft.SharePoint.Client.Runtime")
Only difference is that I am logged in with a domain user on my notebook (although not from the same domain as the user used for SP credentials) and on the server, I am using a local user.
Anyone an idea or a hint?

Answer 1

After some more investigation I finally found the issue.
The server I was testing the script is not joined to a domain. Therefore, no trust is available between the server and SP online what causes the authentication to fail - although without any indication in that direction.
Examining $error[0]|format-list -force was what drove me to test on authentication issues.
Trying the script on different other clients and a domain-joined servers was successfully.
Although no more required, I couldn't find a way to be able to run the script on the workgroup server, SharePointOnlineCredentials does not seem to be able to handle login if no federation is in place...but correct me if I'm wrong