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

Question

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=[e-mail] 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 209.85.223.178) smtp.mailfrom=[e-mail]; Received: from HE1P191MB0203.EURP191.PROD.OUTLOOK.COM (10.172.128.140) by HE1P191MB0137.EURP191.PROD.OUTLOOK.COM (10.172.128.15) 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?

Many Thanks!

Answer 1

From the NDR, it looks the primary SMTP address is invalid or missing. You may first run the following command and see whether the SMTP address is valid:

get-mailbox | fl email