Outbound Delivery error: 550 Unable to relay

Updated 1 month ago by admin

All outbound emails are authenticated.  This is achieved in one of two ways: Server-based or User-based.  If you receive the error, <server>.scanscope.net #550 Unable to relay it means that authentication has failed and has not been configured correctly.  Below are the authentication methods used.

1. By IP address in sending hosts (Server Based)

The IP address or host has not been added to the Outbound Mail section of Product Configuration.  The only information which is required is the external IP address that the server will be connecting to EMS with.  To add an IP address, follow the steps below:

  1. Navigate to Products ⟶ E-mail Security ⟶ Product Configuration ⟶ Outbound Emails.
  2. Click + to create an entry.
  3. Enter the IP address and click on Update to add the entry.
For Office 365, please see the following KB article.

As an SPF record is added to the sending hosts, the following requirements must be met otherwise, the message will be rejected:

  1. The IP address comes from an Office 365 server listed in the SPF record.
  2. The mail from: comes from a domain that is configured in Product Configuration ⟶ Domains
2. SMTP Authentication (User Based)

SMTP authentication is used on a per-user basis where Dynamic IP addresses may be assigned to users.  In this case, the user's account and password setup in the portal will be the SMTP authentication details.

NOTE: You will need to log a case with your Service Provider to enable SMTP Authentication enabled for these users. By default, this feature is not enabled for user accounts.

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