Outbound Delivery error: 550 Unable to relay
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:
- Navigate to Products ⟶ E-mail Security ⟶ Product Configuration ⟶ Outbound Emails.
- Click + to create an entry.
- Enter the IP address and click on Update to add the entry.
As a SPF record is added to the sending hosts the following requirements must be met otherwise the message will be rejected:
- The IP address comes from a Office 365 server listed in the SPF record.
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 maybe assigned to users. In this case, the users account and password setup in the portal will be the SMTP authentication details.