Message 550 5.7.1 resolver.rst.notauthorized

By dcuttler ·
It appears that one user is sending an email to a distribution list on the same server/domain on Exchange 2007 and getting the following bounce back message: 550 5.7.1 resolver.rst.notauthorized.

After checking several posts I have determined that within "Mail Flow Settings"--> "Message Delivery Restrictions" --> the "Require that all senders are authenticated" box is already unchecked.

Any other suggestions would be greatly appreciated.

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Re: 550 5.7.1

by christianshiflet In reply to Message 550 5.7.1 resolve ...

If I understand, a user on your domain is connected to your domain and trying to send email within your domain. Is that correct? Can the user send other messages to individual users on the same domain and not the distribution list? Can they send messages to addresses outside of the domain? That message typically refers to blocked relaying. I would check your Exchange server's send connectors as well as the settings from the user's Outlook. Lastly, is the user possibly sending the message from a mobile device? If so there may be an issue with the mobile device policy (such as the Active Sync Policy) they are accessing.

Let me know if this helps or you have questions. Thanks.

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Re: 550 5.7.1

by dcuttler In reply to Re: 550 5.7.1

First, thanks for such a quick response.

You are correct that the user is on our domain and sending to the list which is also on the same domain. The user can send to recipients on the list individually as well as to addresses not on the list and also not on our domain.

The user is using Outlook client, not OWA and is not using any mobile device. The users individual Outlook settings appear to be exactly the same as the others. Thanks again.

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by christianshiflet In reply to Re: 550 5.7.1

Has the user sent messages to every recipient on the DL successfully or did they test just a few? Also, in Exchange 2007 is the DL a Distribution Group in Active Directory? If so (and if this isn't what you meant you already did), check the mail flow settings for the group, as well. Also, check the members of the DL and see if there are any resource mailboxes on it and check the mail flow settings on them.

Does the bounce message specifically identify one mailbox or the entire DL? Can you add the DL to the To: field, expand it, and then send successfully? Let me know. Plus, if you expand the DL to send, the bounce should identify the specific mailbox that is causing the issue. If it sends successfully, the DL is the problem.

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by dcuttler In reply to Hmm

I am in the process of checking what you suggest but one additional question. It appears as if this is only affecting one user. Would a setting in the DL affect only one user or is there something in this users setting that could be wrong.

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Re: Hmm

by christianshiflet In reply to Hmm

If it is only one user it is probably something to do with that user's account, their profile on their PC, or a rule on their mailbox.

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by dcuttler In reply to Re: Hmm

Apparently the user added herself to a group that was prohibited from sending to those particular distribution lists. I'm embarrassed for not catching this one earlier. Thanks for your time.

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Re: Oops

by christianshiflet In reply to Oops

Always glad to try and help. Glad you figured it out.

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Many thanks to ChristianShiflet

by timmydaniel In reply to Message 550 5.7.1 resolve ...

We had the same 550 5.7.1 notauthorized issue and by going through Christian's suggestion of expanding the DL and isolating the individual user we found a user with a corrupt mailbox preventing received messages.

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