403 Forbidden error while accessing Azure web api using certificate authentication - webclient

Question

I am getting 403 Forbidden exception while accessing simple azure webapi with certificate authentication, only while accessing from asp.net web application. I am using WebClient inherited object to overide GetWebRequest to add client certificate.
public class CertificateWebClient : WebClient
{
private readonly X509Certificate2 certificate;
public CertificateWebClient(X509Certificate2 cert)
{
certificate = cert;
}
protected override WebRequest GetWebRequest(Uri address)
{
HttpWebRequest request = (HttpWebRequest)base.GetWebRequest(address);
request.ClientCertificates.Add(certificate);
return request;
}
}
And I am using the object CertificateWebClient DownloadString function to access the web api.
X509Certificate2 newCertificate = new X509Certificate2("bytearray");
CertificateWebClient webClient = new CertificateWebClient(newCertificate)
{
Proxy = new WebProxy("proxy address")
};
var result = webClient.DownloadString("https://webapiaddress/api/Values");
I am accessing the web api in the similar manner in windows forms and it works absolutely fine.

Answer 1

I could resolve this issue by storing and retrieving the certificate from Azure key vault in Base 64 string format. Using Convert.ToBase64String("raw certificate data") and Convert.FromBase64String("base64 cert string"), so I had to modify the above code as
X509Certificate2 newCertificate = new X509Certificate2(Convert.FromBase64String("base64 cert string"));
Only base 64 format keeps the certificate raw data intact while Adding/Retrieving certificate data to azure key vault.
The Certificate should have been ideally added to Azure key vault certificate store but the project requirement was to store it as key.