Getting “Delivery has failed to these recipients or groups” on every received email

Copper Contributor



In Office 365 I recently converted an email address from a shared mailbox to a user mailbox, but I've noticed that every time we receive an email to that address (even though we DO actually receive it), we get another email seconds later saying the following:


'Delivery has failed to these recipients or groups'


Diagnostic information for administrators:


Generating server: HE1P191MB0137.EURP191.PROD.OUTLOOK.COM IMCEAEX-_o=ExchangeLabs_ou=Exchange+20Administrative+20Group+20+28FYDIBOHF23SPDLT+29_cn=Recipients_cn=99247ae283514c3a9f35f67f189741af-jenny@EURP191.PROD.OUTLOOK.COM Remote Server returned '550 5.2.0 RESOLVER.ADR.MissingPrimary; recipient primary SMTP address is missing: '''


Original message headers:

Authentication-Results: spf=permerror (sender IP is; Received: from HE1P191MB0203.EURP191.PROD.OUTLOOK.COM ( by HE1P191MB0137.EURP191.PROD.OUTLOOK.COM ( with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.820.15; Tue, 5 Jun 2018 10:46:53 +0000 Received: from HE1P191MB0203.EURP191.PROD.OUTLOOK.COM ([::1]) by HE1P191MB0203.EURP191.PROD.OUTLOOK.COM ([fe80::7558:2d5c:f145:3f73%10]) with Microsoft SMTP Server id 15.20.0820.015; Tue, 5 Jun 2018 10:46:53 +0000 Content-Type: application/ms-tnef; name="winmail.dat" Content-Transfer-Encoding: binary


Sending emails seems to work fine, as I've tested both internally & externally. It looks like this was happening before I changed the email over to a user mailbox too, but nobody noticed.

Does anyone know what the issue is?

3 Replies

That's usually an issue with missing/invalid legacyExchangeDN and/or an outdated entry in the Outlook name cache. If the issue happens when you reply to old messages, the best thing to do is add the old legacyExchangeDN as X500 address as detailed here:


If it happens for new messages as well, delete the name cache entry and send a message by either selecting the object directly from the GAL or typing the full email address, without completing it.

Hi Vasil, thanks for the suggestion. The issue happens with all messages our email address receives, regardless of whether we have emailed that address before or not.


I deleted the name cache registry, but it's still happening.


Any other help would be appreciated.


Many thanks,