How to troubleshot HttpWebRequest if X509Certificate is not added properly

Kuler Master 266

Hello all,

I am adding a X509Certificate to the HttpRequest like the following:

HttpWebRequest request = (HttpWebRequest)WebRequest.Create("webserviceurl");

request.ClientCertificates.Clear(); 

X509Certificate certificate = new X509Certificate(
    certificateFilePath, certificatePassword, 
    X509KeyStorageFlags.MachineKeySet | 
    X509KeyStorageFlags.PersistKeySet | 
    X509KeyStorageFlags.Exportable);

if(certificate != null) 
    request.ClientCertificates.Add(certificate);

However, sometimes the certificate is not added correctly or is blocked by something (ISP, Firewall etc. etc.) and we get an error from the web service we send it toward. It happens like 3 times out of 10. Meaning it works 3 times, then this problem occurs or works 5 times and then happens 2 times in a row - no specific pattern of when it happens. How do I troubleshot and figure out what could be the reason for this?

Thank you in advance!

JasonPan - MSFT 5,906 Reputation points Microsoft Vendor

2024-11-05T06:42:11.3033333+00:00

Hi @Kuler Master,

We can try using Try... Catch.. to check if there is any exception.

I'd also like to know how often you mentioned the ten http requests? Because it is possible that webserviceurl server may have some rate limiting configuration.

Best Regards

Jason
Kuler Master 266 Reputation points

2024-11-05T07:53:59.29+00:00

Hello Jason,

Thank you for replying - it's much appreciated. I am using try catch block indeed, but I didn't include it for the sake of clarify. The exception is the following:

The request was aborted: Could not create SSL/TLS secure channel.

Obviously, it is not very helpful because it only implies that the certificate is not included.
Yeah, I talked with their support and they told me that our failing requests arrive without the certificate so they reject them.

Meaning, we have defined the problem but I still don't know where to start looking for the solution.

Talking about the limitation; There is no such limitation at all as we are using the very same WS for years and it always worked fine. Since recently we started getting the above exception.

BTW, we don't use this web service too often. Maybe like 20-30 times per day.

Thank you!

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