Cannot send emails

Can receive, but cannot send emails.  Problem started 2 days ago.  Double checked smtp settings and they seem correct.

log below.
3:17:45 PM   MailExceptions.ItemOperationException: Cannot send message (Email body not accepted with reason:
3:17:45 PM     "See http://pobox.com/~djb/docs/smtplf.html.
3:17:45 PM ")
3:17:45 PM pkhemmer@cuhlaw.com [SMTP]  MailExceptions.SocketException: Sending messages failed with reason:
3:17:45 PM     “Unable to read data from the transport connection: An existing connection was forcibly closed by the remote host.”
3:17:45 PM    at MailClient.Smtp.SmtpSendCommand.Execute(WorkerStatus status)
3:17:45 PM    at MailClient.Commands.Command.Process(WorkerStatus status)
3:17:45 PM pkhemmer@cuhlaw.com [POP3]  Connecting: To pkhemmer@cuhlaw.com
3:17:46 PM pkhemmer@cuhlaw.com [POP3]  Connected: To pkhemmer@cuhlaw.com
3:17:46 PM pkhemmer@cuhlaw.com [POP3]  Downloading messages: From pkhemmer@cuhlaw.com
3:17:47 PM pkhemmer@cuhlaw.com [POP3]  Disconnected: From pkhemmer@cuhlaw.com
3:17:47 PM pkhemmer@cuhlaw.com [POP3]  Disconnected: Done

Hi Paul,
does this occur with all your messages or just a particular message (in a certain case)? What version of eM client are you currently using, can you please check for the exact version number in Help > About?

Can you also please navigate to Tools > Settings > Advanced and turn on SMTP logging for the problematic account?

  1. Save the settings
  2. Restart the application
  3. Replicate the issue
    Once the issue reoccurs, please go back to the advanced settings window and click on “send logs” and send the logs to my email, mcgregor@emclient.com with a reference link to this forum topic.

Thank you,
Paul.