Fix NDR error "550 5.7.12" in Exchange Online
It's frustrating when you get an error after sending an email message. This topic describes what you can do if you see status code 550 5.7.12 or 5.7.12 in a non-delivery report (also known as an NDR, bounce message, delivery status notification, or DSN). You'll see this automated notification when the recipient is configured to reject messages that are sent from outside of its organization.
|
I got this bounce message. How do I fix it? | 
|
I'm an email admin. How do I fix this issue? |
I got this bounce message. How do I fix it?
Only an email admin in the recipient's organization can fix this issue. Contact the email admin and refer them to this information so they can try to resolve the issue for you.
I'm an email admin. How do I fix this issue?
The two methods that will allow an external sender to send messages to the recipient in your organization are described in the following sections.
To open the Exchange admin center (EAC), see Exchange admin center in Exchange Online.
Method 1: Allow all internal and external senders to send messages to this recipient
Open the EAC and use one of the following procedures based on the recipient type.
User mailboxes
New EAC
Go to Recipients > Mailboxes.
Select a mailbox from the list and click it. The mailbox properties screen appears.
Under Mail flow settings, click Manage mail flow settings. The Manage mail flow settings screen appears.
In the Message delivery restriction pane, click Edit. The Message delivery restrictions screen appears.
Clear the check box for Require senders to be authenticated in the Accept messages from section.
Click Save.
Classic EAC**
Go to Recipients > Mailboxes.
Select the mailbox from the list, and then click Edit
. The mailbox properties screen appears.Go to Mailbox features > Message Delivery Restrictions > and then click View details. The message delivery restrictions screen appears.
Clear the check box for Require that all senders are authenticated in the Accept messages from section.
Click OK, and then click Save.
Groups (distribution groups, mail-enabled security groups, and dynamic distribution groups)
Groups in the new EAC
Go to Recipients > Groups.
Select the group from the list and click it. The group properties screen appears.
Click the Settings tab. The group settings screen appears.
Under the Delivery management pane, click Edit delivery management. The Delivery management screen appears.
Choose the radio button for Allow messages from people inside and outside my organization.
Click Save changes.
Groups in the classic EAC
Go to Recipients > Groups > select the group from the list, and then click Edit
. The group properties screen appears.On the left pane, click Delivery management.
Click the radio button for Senders inside and outside of my organization.
Click Save.
Mail users
Important
Currently, editing mail flow settings for a mail user is available only in the Classic EAC.
Go to Recipients > Contacts.
Select the mail user from the list, and then click Edit
. The mail user properties screen appears.Go to Mailbox flow settings > Message Delivery Restrictions and click View details. The Message delivery restrictions screen appears.
Clear the check box for Require that all senders are authenticated in the Accept messages from section.
Click OK, and then click Save.
Shared mailboxes
Shared mailboxes in the new EAC
Go to Recipients > Mailboxes.
Select a shared mailbox from the list and click it. The mailbox properties screen appears.
Under Mail flow settings, click Manage mail flow settings. The Manage mail flow settings screen appears.
In the Message delivery restriction pane, click Edit. The message delivery restrictions screen appears.
Clear the check box for Require senders to be authenticated in the Accept messages from section.
Click Save.
Shared mailboxes in the classic EAC
Go to Recipients > Mailboxes.
Select a shared mailbox from the list, and then click Edit
. The shared mailbox properties screen appears.Go to Mailbox features > Message Delivery Restrictions > and then click View details. The Message delivery restrictions screen appears.
Clear the check box for Require that all senders are authenticated in the Accept messages from section.
Click OK, and then click Save.
Method 2: Use the recipient's allowed senders list
Instead of allowing all external senders to send messages to this recipient, you can use the recipient's allowed senders list to selectively allow messages from all internal senders and the specified external senders.
Notes:
To add an external sender to a recipient's allowed senders list, you must first create a mail contact or a mail user to represent the external sender in your organization.
To add everyone in your organization to a recipient's allowed sender's list, you can create a distribution group or a dynamic distribution group that contains everyone in your organization. After you create this group, you can add it to the recipient's allowed senders list.
The recipient's allowed senders list is different from the organization's allowed senders list for anti-spam that you manage in the EAC at Protection > Spam filter.
To configure the recipient's allowed senders list, open the EAC and use one of the following procedures based on the recipient type.
User mailboxes
New EAC
Go to Recipients > Mailboxes.
Select a user mailbox from the list and click it. The mailbox properties screen appears.
Under Mail flow settings, click Manage mail flow settings. The Manage mail flow settings screen appears.
In the Message delivery restriction pane, click Edit. The Message delivery restrictions screen appears.
Configure the following settings under the Accept messages from section:
Clear the check box for Require senders to be authenticated.
Choose the radio button for Selected senders.
Click + Add sender.
In the Accept messages from screen, select the external senders and the "all internal users" group.
Add the external senders and the "all internal users" group to the list of the allowed senders of the recipient.
When you're finished, click Confirm.
Click Save.
Classic EAC
Go to Recipients > Mailboxes.
Select the mailbox from the list, and then click Edit
. The mailbox properties screen appears.Go to Mailbox features > Message Delivery Restrictions > and then click View details. The message delivery restrictions screen appears.
Configure the following settings in the Accept messages from section:
Clear the check box for Require that all senders are authenticated.
Select Only senders in the following list, and then click Add
. In the Select Members dialog box that opens, select external senders and the "all internal users" group.Add the external senders and the "all internal users" group to the list of the allowed senders of the recipient.
When you're finished, click OK.
Click OK, and then click Save.
Still need help with error code 550 5.7.12?
