Why ParseExact is not converting my variable to DateTime

I am trying to convert a string value to a Datetime value with powershell, but I getting this error:

Excepción al llamar a "ParseExact" con los argumentos "3": "No se puede reconocer la cadena como valor DateTime válido."
En línea: 6 Carácter: 1
+ $CertDate = [DateTime]::ParseExact("$Cert", 'MMM-d-HH:mm:ss-yyyy', $n ...
+ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    + CategoryInfo          : NotSpecified: (:) [], MethodInvocationException
    + FullyQualifiedErrorId : FormatException

This is my code:

$certificatePath = "C:\Users\user\certificate.pem"
$opensslPath = "C:\Program Files\OpenSSL-Win64\bin\openssl.exe"

$Cert = & $opensslPath x509 -in  $certificatePath -noout -enddate
$Cert = $Cert.split("=")[1]
$Cert = $Cert.replace(" ","-")
$Cert = $Cert.replace("--","-")
$Cert = $Cert.replace("-GMT","")
$CertDate = [DateTime]::ParseExact("$Cert", 'MMM-d-HH:mm:ss-yyyy', $null)
$CurrentDate = Get-Date
$DateTime = $CertDate - $CurrentDate
$Date = $DateTime.Days

The output of the variable $cert is:

PS C:\WINDOWS\system32> $Cert
Oct-8-11:05:03-2025

And the variable $Cert is a String Type:

PS C:\WINDOWS\system32> $cert.GetType()

IsPublic IsSerial Name                                     BaseType                                                                                                                                                    
-------- -------- ----                                     --------                                                                                                                                                    
True     True     String                                   System.Object

The $Cert output match with the format indicated in the ParseExact: 'MMM-d-HH:mm:ss-yyyy'

Any idea of what I am doing wrong?

Thanks and BR!

Tried different formts and doesn't worked

Solution

Assuming there are no invisible characters that could be causing this issue, by simply changing the Provider argument from $null to InvariantCulture the issue should be solved.

& {
    $Cert = 'Oct-8-11:05:03-2025'
    [System.Threading.Thread]::CurrentThread.CurrentCulture =
        [cultureinfo]::GetCultureInfo('es-AR')

    [DateTime]::ParseExact($Cert, 'MMM-d-HH:mm:ss-yyyy', [cultureinfo]::InvariantCulture)
    # Correctly parses into: `miércoles, 8 de octubre de 2025 11:05:03`
}

In ParseExact Remarks section you can read the following:

If provider is null, the CultureInfo object that corresponds to the current culture is used.

In Spanish culture a month in the MMM format would end with a ., i.e.: Oct.. This is why using $null fails to parse and also this is proven by, if you add the . it parses correctly:

& {
    # With the `.` after `Oct` this parses corretly in Spanish culture
    $Cert = 'Oct.-8-11:05:03-2025'
    [System.Threading.Thread]::CurrentThread.CurrentCulture =
        [cultureinfo]::GetCultureInfo('es-AR')

    [DateTime]::ParseExact($Cert, 'MMM-d-HH:mm:ss-yyyy', $null)
}