Ошибка MailKit.Security.SslHandshakeException C#

Есть служба, которая мониторит почту, в случае когда приходит письмо, получает вложения и дальше с ними работает. Во время разработки и тестирования на локальном ПК проблем нет, при установки службы на сервер получаю ниже описанную ошибку:

[15.05.2018 12:58:01.559] [MailKit.Net.Imap.ImapClient+d__81.MoveNext()] MailKit.Security.SslHandshakeException: An error occurred while attempting to establish an SSL or TLS connection.

One possibility is that you are trying to connect to a port which does not support SSL/TLS.

The other possibility is that the SSL certificate presented by the server is not trusted by the system for one or more of the following reasons: 1. The server is using a self-signed certificate which cannot be verified. 2. The local system is missing a Root or Intermediate certificate needed to verify the server's certificate. 3. The certificate presented by the server is expired or invalid.

See https://github.com/jstedfast/MailKit/blob/master/FAQ.md#InvalidSslCertificate for possible solutions. ---> System.IO.IOException: Unable to write data to the transport connection: An existing connection was forcibly closed by the remote host. ---> System.Net.Sockets.SocketException: An existing connection was forcibly closed by the remote host at System.Net.Sockets.Socket.Send(Byte[] buffer, Int32 offset, Int32 size, SocketFlags socketFlags) at System.Net.Sockets.NetworkStream.Write(Byte[] buffer, Int32 offset, Int32 size) --- End of inner exception stack trace --- at System.Net.Sockets.NetworkStream.Write(Byte[] buffer, Int32 offset, Int32 size) at System.Net.Security.SslState.StartSendBlob(Byte[] incoming, Int32 count, AsyncProtocolRequest asyncRequest) at System.Net.Security.SslState.ForceAuthentication(Boolean receiveFirst, Byte[] buffer, AsyncProtocolRequest asyncRequest) at System.Net.Security.SslState.ProcessAuthentication(LazyAsyncResult lazyResult) at MailKit.Net.Imap.ImapClient.d__81.MoveNext() --- End of inner exception stack trace --- at MailKit.Net.Imap.ImapClient.d__81.MoveNext() --- End of stack trace from previous location where exception was thrown --- at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task) at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task) at MailKit.Net.Imap.ImapClient.Connect(String host, Int32 port, SecureSocketOptions options, CancellationToken cancellationToken) at EDIService1CConvert.Watcher.ConnectIMAP(), имя метода - ConnectIMAP

Метод ConnectIMAP :

private void ConnectIMAP()
{
    try
    {
        using (CancellationTokenSource IMAPWatcherCancelToken = new CancellationTokenSource())
        {
            ImapClient client = new ImapClient();
            client.Connected += Client_Connected;
            client.Authenticated += Client_Authenticated;

            client.Connect(mailServer, mailPort, isSSL);
            client.Authenticate(userMailLogin, userMailPassword);
            //Директория на почтовом сервере
            IMailFolder inbox = client.Inbox;
            inbox.Open(FolderAccess.ReadWrite);
            inbox.CountChanged += Inbox_CountChanged;
            client.IdleAsync(IMAPWatcherCancelToken.Token);
            Log.Write(null, "IMAPWatcher запущен.", 1);
        }
    }
    catch(Exception ex)
    {
        Log.Write(ex, "ConnectIMAP", 1);
    }
}