Help to resolve SSL/ TLS error despite trying all TLS versions ?

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C#

SSL

WebResponse

ASP.NET4

TLS

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Please any one help me on below error:-


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


Same was working fine using postman with tls and tls1.3 version. but when i try it through ASP.NET 4.8 application. it does not work and gives above error.

In this application, i am using .p12 certificate for using third party api which work on tls & tls1.3 version.

Please guide

when we use tls1.3 than it gives below error:-

The client and server cannot communicate, because they do not possess a common algorithm

What I have tried:

ServicePointManager.Expect100Continue = false;
ServicePointManager.DefaultConnectionLimit = 9999;

ServicePointManager.SecurityProtocol = SecurityProtocolType.Tls13;
OR
ServicePointManager.SecurityProtocol = SecurityProtocolType.Tls12;
OR
ServicePointManager.SecurityProtocol = SecurityProtocolType.Tls11;
OR
ServicePointManager.SecurityProtocol = SecurityProtocolType.Tls;
OR
ServicePointManager.SecurityProtocol = SecurityProtocolType.Ssl;

ServicePointManager.ServerCertificateValidationCallback = (snder, cert, chain, error) => true;