NDR error code 550 5.4.1 "Recipient address rejected: Access denied"

You receive the following NDR error message:

550 5.4.1 Recipient address rejected: Access denied

The NDR is generated when directory-based edge blocking in Microsoft Exchange Online blocks an incoming tin nhắn message because the recipient's tin nhắn address is invalid.

How vì thế I fix this?

If you're an tin nhắn administrator in the recipient's organization, follow these steps until the issue is fixed:

1. Check the spelling of the recipient's tin nhắn address in the NDR.

2. Determine whether the issue affects only one recipient or everyone in the recipient's tên miền. For example, if an tin nhắn message vĩ đại "[email protected]" triggers the NDR, kiểm tra whether messages that are sent vĩ đại other recipients in the "contoso.com" tên miền also trigger the NDR.

3. If the issue affects all recipients in the tên miền, follow these steps vĩ đại resync the domain:

   1. In the Exchange admin center, select Mail flow > Accepted domains, and then select the affected tên miền.

   2. In the flyout pane for the tên miền, switch the tên miền type from Authoritative vĩ đại Internal relay, and then switch back vĩ đại Authoritative. For more information, see Manage accepted domains in Exchange Online.

4. If the issue is limited vĩ đại a specific recipient who has an on-premises user mailbox in an Exchange hybrid environment, and your organization uses directory sync vĩ đại push changes vĩ đại Microsoft Entra ID, reset the SMTP proxy address of the recipient's mailbox. To reset, change the proxy address vĩ đại a temporary address, and then revert it vĩ đại the original proxy address.

   Note: When you make changes vĩ đại the on-premises mailbox, allow up vĩ đại 24 hours for directory-based edge blocking vĩ đại fully update.

5. If the issue is limited vĩ đại a specific recipient that's an on-premises mail-enabled public thư mục in an Exchange hybrid environment, verify that the thư mục is synced vĩ đại Exchange Online. If the thư mục doesn't appear in Exchange Online, use the Sync-ModernMailPublicFolder PowerShell script vĩ đại copy your on-premises mail-enabled public folders vĩ đại Exchange Online.

6. If the issue is limited vĩ đại a specific recipient that's an on-premises dynamic distribution group in an Exchange hybrid environment, create a mail tương tác in Exchange Online that has the same external tin nhắn address as the dynamic distribution group. An on-premises dynamic distribution group in a hybrid environment can't be synced vĩ đại Exchange Online.

Note: When you mix up an Exchange environment, we recommend that you temporarily mix the accepted tên miền type vĩ đại Internal Relay. After you add all intended recipients vĩ đại Exchange Online and they are fully replicated, change the tên miền type vĩ đại Authoritative vĩ đại block all messages vĩ đại recipient SMTP addresses that aren't in Exchange Online.