Hi!

We have some sites running CMS 11 and one site running CMS 12 (all on-premise). All sites are using Optimizely Forms and its built in function allowing form posts to be sent with e-mail.

However, we're now struggling with a problem where some e-mails randomly disappear.

In our log files we've found the following:

Failed to send email
System.AggregateException: One or more errors occurred. (The SMTP server has unexpectedly disconnected.)
 ---> MailKit.Net.Smtp.SmtpProtocolException: The SMTP server has unexpectedly disconnected.
   at MailKit.Net.Smtp.SmtpStream.ReadAheadAsync(Boolean doAsync, CancellationToken cancellationToken)
   at MailKit.Net.Smtp.SmtpStream.ReadResponseAsync(Boolean doAsync, CancellationToken cancellationToken)
   at MailKit.Net.Smtp.SmtpClient.SendCommandAsync(String command, Boolean doAsync, CancellationToken cancellationToken)
   at MailKit.Net.Smtp.SmtpClient.SendEhloAsync(Boolean ehlo, Boolean doAsync, CancellationToken cancellationToken)
   at MailKit.Net.Smtp.SmtpClient.EhloAsync(Boolean doAsync, CancellationToken cancellationToken)
   at MailKit.Net.Smtp.SmtpClient.ConnectAsync(String host, Int32 port, SecureSocketOptions options, Boolean doAsync, CancellationToken cancellationToken)
   at EPiServer.Notification.Internal.SmtpClientImplementation.SendAsync(MimeMessage message)
   --- End of inner exception stack trace ---
   at System.Threading.Tasks.Task.ThrowIfExceptional(Boolean includeTaskCanceledExceptions)
   at System.Threading.Tasks.Task.Wait(Int32 millisecondsTimeout, CancellationToken cancellationToken)
   at System.Threading.Tasks.Task.Wait()
   at EPiServer.Forms.Implementation.Actors.SendEmailAfterSubmissionActor.<>c__DisplayClass13_0.<SendMessage>b__2()

Has anyone else experienced a similar problem?

Is there some way to extend the logging so that we can get more information?

Appreciate all the help we can get :-)