exchange 2003 outlook

Posted on 2009-05-01
Last Modified: 2013-11-22
i have an exchange 2003 server and the clients use outlook 2003. i just want to confirm the error i'm having. the error on the client states

"there was a smtp communication problem with recipient's email server #5.5.0 smtp; 550 recipient address rejected: user unknown"

i assume this problem is just as it states, the address is bad, so for instance if the client sent to, as the message states, there isn't an so maybe the client typed the name incorrectly, or there isn't an, or there was an but it has change, or was removed. are these assumptions correct?
Question by:JeffBeall
    LVL 38

    Accepted Solution

    The 5.5.0 error is pretty generic. However, in the case of what you have posted above, I would accept the added reason for rejection and assume that the recipient's email address was invalid for whatever reason. As you said, it could have never existed, it could have been removed for some reason, or it could have been changed; or the sender could have simply mis-typed the address.  In these cases, I usually advise the sender (your user) to contact the recipient and ask him/her to send an email to your user, and then they can reply to that email, ensuring that they have the correct address.  If the reply email still doesn't go through, then the NDR is giving you invalid information and there is some other communication issue between your server and the recipient's email server.
    LVL 1

    Author Closing Comment

    Thanks for the help. I think I'll try to have the client contact the person in question and do like you said and have them send an email.

    Expert Comment

    Hi JeffBeall,
    Delivery notification error 5.xx is a permanent delivery failure
    Possible issues.
    1.      Remote computer may reject your domain.
    2.      May be issue with the recipient SMTP relay server.
    3.      Due to recipient unavailable.
    You can find same information with the help of message header.
    For more information about the Delivery status notification errors visit the following link

    Featured Post

    What Should I Do With This Threat Intelligence?

    Are you wondering if you actually need threat intelligence? The answer is yes. We explain the basics for creating useful threat intelligence.

    Join & Write a Comment

    Create high volume marketing opportunities using email signatures with these top 10 DOs and DON'Ts of email signature marketing.
    Use these top 10 tips to master the art of email signature design. Create an email signature design that will easily wow recipients, promote your brand and highlight your professionalism.
    In this video we show how to create a Shared Mailbox in Exchange 2013. We show this process by using the Exchange Admin Center. Log into Exchange Admin Center.: First we need to log into the Exchange Admin Center. Navigate to the Recipients >> Sha…
    The basic steps you have just learned will be implemented in this video. The basic steps are shown to configure an Exchange DAG in a live working Exchange Server Environment and manage the same (Exchange Server 2010 Software is used in a Windows Ser…

    728 members asked questions and received personalized solutions in the past 7 days.

    Join the community of 500,000 technology professionals and ask your questions.

    Join & Ask a Question

    Need Help in Real-Time?

    Connect with top rated Experts

    19 Experts available now in Live!

    Get 1:1 Help Now