Hi one of the user in our domain tried to send a calendar appointment to two recipients (one inside the domain and other external domain) as soon as they acknowledge the request the out look is trying to send the appointment repeatedly and ndrs with error 5.1.3 start flowing to his email.

We are using outlook 2010 and server is 2003

The ndr is as fllows

 

From: System Administrator Sent: Monday, 7 October 2013 1:45 p.m. To: sender Subject: Undeliverable:XYZ / AAA Monthly CatchUp

 

 

 

 

 

Your message did not reach some or all of the intended recipients.

 

 

 

      Subject:    XYZ / AAA Monthly CatchUp

 

      Sent:7/10/2013 1:44 p.m.

 

 

 

The following recipient(s) cannot be reached:

 

 

 

      domain user on 7/10/2013 1:45 p.m.

 

            The format of the e-mail address is incorrect.  Check the address, look up the recipient in the Address Book, or contact the recipient directly to find out the correct address.

 

            <domain.co.nz #5.1.3>

 

 

 

      external domain user on 7/10/2013 1:45 p.m.

 

            The format of the e-mail address is incorrect.  Check the address, look up the recipient in the Address Book, or contact the recipient directly to find out the correct address.

 

            <domain.co.nz #5.1.3>