C#: Could Not Establish Trust Relationship For SSL/TLS Secure Channel — SOAP

This error usually occurs when trying to make an HTTP request to a server using an SSL certificate that is not trusted by the client. Here are a few potential solutions to resolve this issue:

  1. Update the trust store: Check if the SSL certificate used by the server is valid and trusted. If not, update the trust store on the client machine to include the certificate authority (CA) that issued the SSL certificate. You can download and install the CA certificate in the trust store using the MMC (Microsoft Management Console) snap-in or programmatically using the X509Certificate2 class.

  2. Ignore SSL certificate validation: Use the ServicePointManager.ServerCertificateValidationCallback property to ignore SSL certificate validation. This should be used with caution as it exposes the client to potential security risks by trusting any server certificate. Here’s an example of how to implement it:

ServicePointManager.ServerCertificateValidationCallback += (sender, cert, chain, sslPolicyErrors) => true;
  1. Check system clock and time zone: SSL certificate validation relies on the system clock being accurately set. Make sure the client server’s clock and time zone are properly configured.

  2. Verify server’s SSL configuration: There might be issues with the server’s SSL configuration. Ensure that the server is properly configured with valid SSL certificates and supported protocols (such as TLS 1.2 or later). Check for any certificate chain issues or expired certificates.

  3. Disable specific SSL/TLS versions: By default, .NET Framework supports multiple SSL/TLS versions. If the server only supports a specific version and the client is using an older version, it can cause the trust relationship error. To disable specific versions, you can modify the ServicePointManager.SecurityProtocol property. For example, to disable SSLv3 and use only TLS 1.2:

ServicePointManager.SecurityProtocol = SecurityProtocolType.Tls12;

Try one or more of these solutions and see if it resolves the "Could not establish trust relationship for SSL/TLS secure channel" error when making a SOAP request in C#.

About the Author Rex

I'm a passionate tech blogger with an insatiable love for programming! From my early days tinkering with code, I've delved into web dev, mobile apps, and AI. Sharing insights and tutorials with the world is my joy, connecting me to a global community of like-minded tech enthusiasts. Python holds a special place in my heart, but I embrace all challenges. Constantly learning, I attend tech conferences, contribute to open-source projects, and engage in code review sessions. My ultimate goal is to inspire the next generation of developers and contribute positively to the ever-evolving tech landscape. Let's code together!