Https

Modern versions of Unity (2020+) no longer require the below code as they support current TLS versions

On platforms that are mono based (i.e not Windows) and when using the .NET 2.0 api you may encounter certificate validation errors when using HTTPS. This is because mono doesn't include any root certificates by default. You can add the following code to handle the certificate validation event and automatically accept all certificates. However this is very insecure so you should add your own validation logic

C#
System.Net.ServicePointManager.ServerCertificateValidationCallback += (o, certificate, chain, errors) =>
{
    return true;
};