<Recipient email address>
There's a problem with the recipient's mailbox. Please try resending the message. If the problem continues, please contact your email admin.
Remote Server returned '550 5.2.0 RESOLVER.ADR.BadPrimary; recipient primary SMTP address is missing or invalid'
- The primary SMTP address was not added to the external contact’s proxy address.
- A legacy proxy address is specified in the external contact’s proxy address.
- If the user is using Microsoft Outlook to send mail, clear the external contact's name from the Outlook Auto-Complete list. For more information about how to do this, see Delete a name from the Auto-Complete list.
If this doesn't resolve the problem, or if the user is using Outlook Web App, go to step 2.
- Make sure that the proxy address is set correctly in Office 365. To do this, follow these steps:
- Sign in to Office 365, and then open the Exchange admin center.
- Click Contacts, select the external recipient, click Edit (), and then click general.
- In the External email address box, make sure that the email address exists, that it's correct, and that it's formatted correctly.
For example, SMTP:firstname.lastname@example.org is an external email address that's formatted correctly.
- If you have an Exchange hybrid deployment, make sure that the proxy address of the Active Directory mail contact object is set to the correct email address. If it's not, update the SMTP value, and then run directory synchronization.
Article ID: 3076419 - Last Review: Jan 5, 2017 - Revision: 1