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Article Id 281253
Description This article describes how to resolve the error '550 Domain is not a protected domain'.
Scope FortiMail Cloud, Office 365.

From Office 365, it is necessary to have two MX records as example below:


With these MX records, it is possible to tell Fortimail Cloud how to route emails.


It is necessary to be careful which MX record is used for the Inbound connector and which one for the outbound connector.

Usually, the error '550 Domain is not a protected domain' is due to FortiMail receiving emails from the incorrect connector.


For example, to configure at office365, go to Exchange Admin Center -> Mail Flow -> Connectors -> Add a connector and set '', but if this mx record is pointed as outbound and is used for inbound, the '550 domain error' will appear.




It is necessary to specify which MX record will be for inbound or outbound in other to route emails properly.