Update: This works for .NET Core 2.2, 3.0 and 3.1 too

You can override SSL cert check on a HTTP call with the a anonymous callback function like this

using (var httpClientHandler = new HttpClientHandler())
{
   httpClientHandler.ServerCertificateCustomValidationCallback = (message, cert, chain, errors) => { return true; };
   using (var client = new HttpClient(httpClientHandler))
   {
       // Make your request...
   }
}

Additionally, I suggest to use a factory pattern for HttpClient because it is a shared object that might no be disposed immediately and therefore connections will stay open.

Update:

As mentioned below, not all implementations support this callback (i.e. platforms like iOS). In this case, as the docs say, you can set the validator explicitly:

handler.ServerCertificateCustomValidationCallback = HttpClientHandler.DangerousAcceptAnyServerCertificateValidator;

This works too for .NET Core 2.2, 3.0 and 3.1

Old answer, with more control but may throw PlatformNotSupportedException:

You can override SSL cert check on a HTTP call with the a anonymous callback function like this

using (var httpClientHandler = new HttpClientHandler())
{
   httpClientHandler.ServerCertificateCustomValidationCallback = (message, cert, chain, errors) => { return true; };
   using (var client = new HttpClient(httpClientHandler))
   {
       // Make your request...
   }
}

Additionally, I suggest to use a factory pattern for HttpClient because it is a shared object that might no be disposed immediately and therefore connections will stay open.

You can override SSL cert check on a HTTP call with the a anonymous callback function like this

using (var httpClientHandler = new HttpClientHandler())
{
   httpClientHandler.ServerCertificateCustomValidationCallback = (message, cert, chain, errors) => { return true; };
   using (var client = new HttpClient(httpClientHandler))
   {
       // Make your request...
   }
}

Additionally, I suggest to use a factory pattern for HttpClient because it is a shared object that might no be disposed immediately and therefore connections will stay open.

Update: This works for .NET Core 2.2, 3.0 and 3.1 too

You can override SSL cert check on a HTTP call with the a anonymous callback function like this

using (var httpClientHandler = new HttpClientHandler())
{
   httpClientHandler.ServerCertificateCustomValidationCallback = (message, cert, chain, errors) => { return true; };
   using (var client = new HttpClient(httpClientHandler))
   {
       // Make your request...
   }
}

Additionally, I suggest to use a factory pattern for HttpClient because it is a shared object that might no be disposed immediately and therefore connections will stay open.