New-Object : Cannot find an overload for “PSCredential” and the argument count: “2”

Question

I want an email to be sent to more than one recipients, and also I don't want to prompt for the username and password. So I have used the below string conversion, but then I'm facing the below error message.

Could you please suggest your answers to rectify this issue?

[string] [ValidateNotNullOrEmpty()] $secpasswd = "Q$$777LV"
$secpasswd = ConvertTo-SecureString -String "Q$$777LV" -AsPlainText -Force
$mycreds = New-Object System.Management.Automation.PSCredential (“test”, $secpasswd)

Error message:

New-Object : Cannot find an overload for “PSCredential” and the argument count: “2”

Answer 1

Your first statement makes $secpasswd a variable of the type [string]. Because of that the SecureString object that you create with your second statement is automatically converted to a string. Because of this the two statements

[string]$secpasswd = "something"
$secpasswd = ConvertTo-SecureString -String "something" -AsPlainText -Force

are effectively the same as

$secpasswd = 'System.Security.SecureString'

Since the PSCredential constructor expects a string and a SecureString object, not two strings, it throws the error you observed.

To fix the issue either don't force the variable to the type [string]:

[ValidateNotNullOrEmpty()]$secpasswd = "something"
$secpasswd = ConvertTo-SecureString -String $secpasswd -AsPlainText -Force
$mycreds = New-Object Management.Automation.PSCredential ("test", $secpasswd)

or use different variables for plaintext and secure string password:

[string][ValidateNotNullOrEmpty()]$passwd = "something"
$secpasswd = ConvertTo-SecureString -String $passwd -AsPlainText -Force
$mycreds = New-Object Management.Automation.PSCredential ("test", $secpasswd)

Answer 2

This error will not rise if data type is defined for secure string.

[String] [ValidateNotNullOrEmpty()] $secpasswd = "Q$$777LV"    
[SecureString] $secpasswd = ConvertTo-SecureString -String "Q$$777LV" -AsPlainText -Force
[PSCredential] $mycreds = New-Object System.Management.Automation.PSCredential (“test”, $secpasswd)