The SSL connection could not be established, see inner exception. The remote certificate is invalid according to the validation procedure

[egorychmaster]

Hello

Installed the Microsoft.Exchange.WebServices.NETStandard 1.1.3 package via nuget, the letter via the Exchange service is successfully sent via the Windows OS Under Linux, Debian no longer works.

I had to download the weight of the project source and connect it to the project. In this case, sending does not work under Windows and under Linux.

I use a component under Debian to connect to Exchang server. Debian in docker. I use Core 2.2 Sending an email.

public void Send(MailMessage mailMessage)
{
	var service = GetService();

	if (service != null)
	{
		EmailMessage emailMessage = new EmailMessage(service)
		{
			From = new EmailAddress(ewsConnection.MailBox),
			Subject = mailMessage.Subject,
			Body = mailMessage.Body,
		};

		if (mailMessage.Adresses != null)
		{
			foreach (var email in mailMessage.Adresses)
			{
				emailMessage.ToRecipients.Add(new EmailAddress(email));
			}
		}

		emailMessage.Send();
	}
}

private ExchangeService GetService()
{
	ExchangeService service = null;
	ExchangeVersion version;
	if (Enum.TryParse<ExchangeVersion>(ewsConnection.Version, out version))
	{
		service = new ExchangeService(version);

		service.Credentials = new WebCredentials(ewsConnection.Login, ewsConnection.Password);
		service.Url = new Uri(ewsConnection.Host);

		// Проверка сертификата 
		ServicePointManager.ServerCertificateValidationCallback = delegate { return true; };
	}

	return service;
}

Submit Error:

The SSL connection could not be established, see inner exception. The remote certificate is invalid according to the validation procedure.

What can I do?

[tjmoore]

See also #25

ServicePointManager.ServerCertificateValidationCallback is not supported in .NET Core it seems even if documentation says .NET Core, particularly as this library now uses HttpClient.