expected e-mails are delayed

I have 2 domains that are unable to get e-mail through to us, they both get the following delayed message. Oddly enough both are using pefora.net as a mailer-daemon. We are receiving e-mail fine except for 2 domains. Here is the syntax of one of the delayed messages:

-----Original Message-----From: Mail Delivery System [mailto:mailer-daemon@domain.net] Sent: Saturday, December 17, 2011 2:14 PMTo: giovanna@domain.caSubject: Warning: message delayed 24 hours This message was created automatically by mail delivery software. A message that you sent has not yet been delivered to one or more ofits recipients after 24 hours. The message has not yet been delivered to the following addresses: <tunderwood@domain2.ca> host mail.domain2.ca[69.159.xxx.84]:mail transaction abortedhost mail.domain2.ca[69.159.xxx.84]:mail transaction abortedhost mail.domain2.ca[69.159.xxx.84]:mail transaction aborted No action is required on your part. Delivery attempts will continue forsome time, and this warning may be repeated at intervals if the messageremains undelivered. Eventually the mail delivery software will give up,and when that happens, the message will be returned to you. --- The header of the original message is following. --- Received: from giovanna (d221-xx-138.commercial.cgocable.net[216.221.xx.138])by mrelay.domain.net (node=mrus3) with ESMTP (Nemesis)id 0M6zfx-1Qpy661xjB-00xJSh; Fri, 16 Dec 2011 14:07:04 -0500From: "Giovanna" <giovanna@domain.ca>To: "'Todd '" <tunderwood@domain2.ca>References:<DF891863264D1E4798924B571B998EB425E0258C17@mail-sdg.SDGCOUNTIES.LOCAL>In-Reply-To:<DF891863264D1E4798924B571B998EB425E0258C17@mail-sdg.SDGCOUNTIES.LOCAL>Subject: RE: Quote pleaseDate: Fri, 16 Dec 2011 13:56:42 -0500Message-ID:<!&!AAAAAAAAAAAYAAAAAAAAAPoDw4316vlOkunH0EqoknjCgAAAEAAAANxTPqzen+hGmqiZEkLOYtwBAAAAAA==@domain.ca>MIME-Version: 1.0Content-Type: multipart/mixed;boundary="----=_NextPart_000_003B_01CCBBFA.8B70B7E0"X-Mailer: Microsoft Office Outlook 12.0Thread-Index: Acy7aiTgWOm+GigJQ6SK3lETr1uCcAAqGUXwContent-Language: en-usDisposition-Notification-To: "Giovanna" <giovanna@domain.ca>X-Provags-ID: V02:K0:N+5DSC7ens/J0xAqLsIzqgPgLUEOBInZURtNx/1ZhOr53sFJFuCwQ4qlcfUBXXgAgLKAQL9KQTKTjgVbIyicHQ+rBBpP05T64kpiCVB+VcPJwPmQobffQZej+40CYoP913u6sfk5yZ4/GE+NV7+aPrC7Xm+9eNZHjaPexv316DPUuN0wrf74Awr9YNiwkY5+AAgNw38XRQ+69xDc+LbE05xGKH8ieL2CZTM+TtZrWaCrBSqXa+xuICOOydpdxHxJxXztRoI2faqJooGVOk39HOc0dQwngxzErHGIxcr2N73kdRKxn6GLrcmVl7lypDqTjsM1qDsLKjcNelbZbngIObH1IaIMK69cs80KifdgZgNmtScyOlc89kqUQSvhQOC1Yehps2V5TWy5OexPedbsIL6EDaxx7mjR9JN40F7jqiG9CT7H2IjJR1lTHF6zGymL8eR+3DHRMDYijcmdAXkDHA==