API/Powershell ZVM authentication

Powershell version: 5.1 / ZVR Version: 5.5 Update1

I’m trying to do some testing with PowerShell and rest API. When using an example script from the White Paper “Automating Zerto Virtual Replication with PowerShell and REST APIs” (page 9) I’m having some authentication issues. I receive the exception error below. The problem seems to be, at some point during the script it changes the user name by using two “\\”, even though I enter the user name as “blah\username”. I’ve tried various ways of inserting the user name, but the “\\” keeps appearing and this is what seems to be causing the auth failure.

Any suggestions on why the extra back slash is appearing?

Exception : System.Net.WebException: The remote server returned an error: (401) Unauthorized.
at Microsoft.PowerShell.Commands.WebRequestPSCmdlet.GetResponse(WebRequest request)
at Microsoft.PowerShell.Commands.WebRequestPSCmdlet.ProcessRecord()
TargetObject : System.Net.HttpWebRequest
CategoryInfo : InvalidOperation: (System.Net.HttpWebRequest:HttpWebRequest) [Invoke-WebRequest], WebException
FullyQualifiedErrorId : WebCmdletWebResponseException,Microsoft.PowerShell.Commands.InvokeWebRequestCommand
ErrorDetails : {“Message”:”Failed logging in to blah-vcenter with username blah\\username. Error was ‘Cannot complete login due to an incorrect user name or
password.'”}
InvocationInfo : System.Management.Automation.InvocationInfo
ScriptStackTrace : at <ScriptBlock>, <No file>: line 59
PipelineIterationInfo : {}
PSMessageDetails :

You cannot call a method on a null-valued expression.
At line:67 char:1
+ $xZertoSession = $xZertoSessionResponse.headers.get_item(“x-zerto-ses …
+ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ CategoryInfo : InvalidOperation: (:) [], RuntimeException
+ FullyQualifiedErrorId : InvokeMethodOnNull