Undeliverable message is returning when sending mail to NON SMTP Address format

Hello ,

We have a requirement to send fax from outlook client to rightfax server 

Softwares :

Exchange Server 2013

Outlook 2007/2010/2013

The approach we have thought like below .

1. Email Address format is like [RFAX:John Doe@/FN=555-555-1212]

   2.  Created one user mail box called "RightFax" to these fax mails.

         3. Transport rule to redirect   mails to "RightFax" user when recipient email address contains word "RFAX"

The issue is like below 

          When we send mail through outlook client it is returning undeliverable mail to sender like below

From  : System Administrator

SUbject : Undeliverable

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

The following recipient(s) cannot be reached None of your e-mail accounts could send to this recipient
RFAX:John Doe@/FN=555-555-1212

Could you please us on this.

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Regards

Yugandhar Vanam