SSL exception on Windows 7

[shabakett]

public static T Rest<T>(string baseAddress, int requestTimeoutSeconds, params string[] defaultRequestHeaders)
{
	var httpClientHandler = new HttpClientHandler { ServerCertificateCustomValidationCallback = (message, cert, chain, errors) => { return true; } };

	var httpClient = new HttpClient(httpClientHandler)
	{
		BaseAddress = new Uri(baseAddress),
		Timeout = TimeSpan.FromSeconds(requestTimeoutSeconds),
	};

	for (int i = 0; i < defaultRequestHeaders.Length; i += 2)
	{
		if (defaultRequestHeaders[i] != null)
		{
			httpClient.DefaultRequestHeaders.Remove(defaultRequestHeaders[i]);
			httpClient.DefaultRequestHeaders.Add(defaultRequestHeaders[i], defaultRequestHeaders[i + 1]);
		}
	}

	return new RestClient(httpClient).For<T>();
}

public interface IApi
{
	[Post("/login")]
	Task<api_token> LoginAsync();
}

var apiLogin = U_COMMON.Rest<IApi>("https://api.myservice.com:4443", 30, "Authorization", $"Basic <some-credential>");
var token = await apiLogin.LoginAsync(); 

• the app is x86 assembly with .NET 5.0
• .NET 5.0 runtimes are installed (both x86 and x64)
• .NET framework 4.8 is installed

it works with Win10 x64 but with Win7 Sp1 x64 it generates:

The SSL connection could not be established, see inner exception.

• the inner exception is empty

• I've already added these registry entries:

  Windows Registry Editor Version 5.00

  [HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Protocols\TLS 1.0\Client] "DisabledByDefault"=dword:00000000 "Enabled"=dword:00000001

  [HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Protocols\TLS 1.1\Client] "DisabledByDefault"=dword:00000000 "Enabled"=dword:00000001

  [HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Protocols\TLS 1.2\Client] "DisabledByDefault"=dword:00000000 "Enabled"=dword:00000001

  [HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Protocols\TLS 1.3\Client] "DisabledByDefault"=dword:00000000 "Enabled"=dword:00000001

  [HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Internet Settings\WinHttp] "DefaultSecureProtocols"=dword:0xAA0 [HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\Microsoft\Windows\CurrentVersion\Internet Settings\WinHttp] "DefaultSecureProtocols"=dword:0xAA0

  [HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft.NETFramework\v2.0.50727] "SystemDefaultTlsVersions"=dword:00000001 "SchUseStrongCrypto"=dword:00000001 [HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft.NETFramework\v4.0.30319] "SystemDefaultTlsVersions"=dword:00000001 "SchUseStrongCrypto"=dword:00000001

  [HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\Microsoft.NETFramework\v2.0.50727] "SystemDefaultTlsVersions"=dword:00000001 "SchUseStrongCrypto"=dword:00000001 [HKEY_LOCAL_MACHINE\SOFTWARE\WOW6432Node\Microsoft.NETFramework\v4.0.30319] "SystemDefaultTlsVersions"=dword:00000001 "SchUseStrongCrypto"=dword:00000001

[canton7]

This exception is being thrown by the underlying HttpClient -- it's not caused by RestEase. You should be able to replicate it by using a HttpClient directly.

I'm afraid I can't help here.