Cannot set app to use system default TLS version by adding appcontext settings in web.config

Question

According to .net guidance of TLS protocol programming, it suggests to config security via appcontext switch when your project targets on .net 4.6. This way works when add a

Answer 1

AppContext switches usage in web config file:

<appSettings>
    <add key="AppContext.SetSwitch:Switch.System.Net.DontEnableSchUseStrongCrypto" value="false" />
    <add key="AppContext.SetSwitch:Switch.System.Net.DontEnableSystemDefaultTlsVersions" value="false" />
</appSettings>

https://github.com/dotnet/docs/issues/6675