$userName = $args[0]
$password = $args[1]
$hostName = $args[2]
Add-Type -AssemblyName System.DirectoryServices.AccountManagement
Function Validate-Credentials{
    $principalContext = New-Object System.DirectoryServices.AccountManagement.PrincipalContext("Machine","$hostname")
    $validate=$principalContext.ValidateCredentials($userName, $passWord)
    if($validate) {
        return $true
    }
    elseif($validate -eq $false) {
        throw "Bad username or Password"
    }
    else {
        throw $_.Exception.InnerException
    }
}
try {
    Validate-Credentials
}
catch {
    throw $_.Exception.InnerException
}