Jenkins管道凭据变量未通过

Question

似乎无法弄清楚这一点，当我在管道中运行以下步骤时，变量似乎为空：

        steps {
            withCredentials([certificate(credentialsId: 'pfxCert', keystoreVariable: 'pfxPath', passwordVariable: 'pfxPassword')]) {
                powershell '''
                $keyContainerName = "somekey123"
                $cert = New-Object System.Security.Cryptography.X509Certificates.X509Certificate2
                $cert.Import($pfxPath, $pfxPassword, [System.Security.Cryptography.X509Certificates.X509KeyStorageFlags]::Exportable)
                $exportPrivateKeyInformation = $true
                $certXml = $cert.PrivateKey.ToXmlString($exportPrivateKeyInformation)
                $csp = New-Object System.Security.Cryptography.CspParameters
                $csp.KeyContainerName = $keyContainerName
                $csp.Flags = [System.Security.Cryptography.CspProviderFlags]::UseMachineKeyStore -bor [System.Security.Cryptography.CspProviderFlags]::NoPrompt # -bor is biwise or
                $csp.KeyNumber = [System.Security.Cryptography.KeyNumber]::Signature
                $rsa = New-Object System.Security.Cryptography.RSACryptoServiceProvider $csp
                $rsa.FromXmlString($certXml)
                $rsa.Clear()
                '''
            }

以下是错误输出：

powershell.exe : Exception calling "Import" with "3" argument(s): "Array may not be empty or null.

我还可以使用秘密文本凭据进行下一步，但是它使用bat而不是powershell。有人知道我在做什么错吗？预先感谢。