Cant test handling of AWS exceptions because constructors are internal ?

gistfile1.cs

using System;
using System.Reflection;

namespace MyLib.Tests
{
    public class AwsExceptionFactory<T>
    {
        // amazon exceptions have internal constructors and so have to use reflection to create instances
        public static T GetException()
        {
            return (T)Activator.CreateInstance(typeof(T),
                                               BindingFlags.NonPublic | BindingFlags.Instance, null, new object[] { "Mock Exception Message" }, null);
        }
    }
}

//This can then be used thus (uses NSubstitue for mocks) :
[Test]
        public void IfServiceExceptionIsThrownDoNotUpdateMailStatusToSent()
        {
            var client = Substitute.For<AmazonSimpleEmailService>();
            var mailrepo = Substitute.For<IMailRepository>();
            var config = Substitute.For<IConfiguration>();
         
            client.SendEmail(Arg.Any<SendEmailRequest>()).Returns((x => { throw AwsExceptionFactory<AmazonSimpleEmailServiceException>.GetException(); }));

            var sesMailSender = new SesMailSender(config, client, mailrepo);
            sesMailSender.SendMail(new Mail());

            mailrepo.DidNotReceive().UpdateMailStatus(Arg.Any<Mail>(), Arg.Any<SendStatus>());
        }