Facing issue while create the events using MS graph API - api

Question

I have tried this code to generate the token:
public async Task Authenticate() {
MultipartFormDataContent content = new MultipartFormDataContent();
content.Add(new StringContent(_clientId), "client_id");
content.Add(new StringContent(_clientSecret), "client_secret");
content.Add(new StringContent("client_credentials"), "grant_type");
content.Add(new StringContent(".default"), "scope");
try {
var task = _client.PostAsync(new Uri(string.Format("https://login.microsoftonline.com/{0}/oauth2/v2.0/token", _tenantId)), content);
var res = task.GetAwaiter().GetResult();
if (res.StatusCode == System.Net.HttpStatusCode.OK) {
JsonDocument resJSON = await JsonDocument.ParseAsync(await res.Content.ReadAsStreamAsync());
_accessToken = resJSON.RootElement.GetProperty("access_token").GetString();
lock(this) {
_expiresAt = DateTime.UtcNow.AddSeconds(resJSON.RootElement.GetProperty("expires_in").GetInt16());
}
} else
throw new Exception(res.ReasonPhrase);
} catch (WebException ex) {
// handle web exception
}
}
But I got the error like
error_description=AADSTS1002016: You are using TLS version 1.0, 1.1 and/or 3DES cipher which are deprecated to improve the security posture of Azure AD. Your TenantID is: 334xxxx. Please refer to https://go.microsoft.com/fwlink/?linkid=2161187 and conduct needed actions to remediate the issue. For further questions, please contact your administrator.
Trace ID: c8a502xxxx
Correlation ID: 325a1dxxxxx
Timestamp: 2022-08-04 13:35:23Z
But the same code works in console application.While using this code inside the dll it throws the exception.All the versions are same - .net framework,System.text.json,system.memory etc.
Please help me to sort out this.

Answer 1

According to this page the default TLS version that is used, depends on the targeted .net version and the used operating system.
Targeting .net framework 4.8 should default to TLS1.2 on Windows 10/11
Any change that you are using an older version of either? Or that you are setting the tls version explicitly somewhere in your application?
Also using lock inside an asynchronous method is bad practice and might deadlock your code.

Answer 2

When I use .NET Framework 4.6.1, I encounter the same problem. After I switched the version to 4.7.2, the problem was not solved until I explicitly specified the version in Web.config.
<httpRuntime targetFramework="4.7.2" />