ERROR: 550 5.7.51 TenantInboundAttribution; There is a partner connector configured that matched the message's recipient domain. The connector had either the RestrictDomainsToIPAddresses or RestrictDomainsToCertificate set

Last Modified

Tue Aug 25 17:30 GMT 2020

Description

  • Messages display a status of "bounced" in Mail Assure.
  • NDR received by sender and Delivery data column in Mail Assure Control Panel shows 550 5.7.51 TenantInboundAttribution; There is a partner connector configured that matched the message's recipient domain. The connector had either the RestrictDomainsToIPAddresses or RestrictDomainsToCertificate set"
  • Issue occurs when recipient domain is hosted in Exchange Online ( Microsoft 365)

Environment

  • Mail Assure

Solution

  • Error is a Microsoft rejection error code.
  • This error indicates that the recipient domain has a connector set up to restrict senders by IPs or Certificates, or the sending organization has set up a connector with the recipient's organization or vice versa.
  • The recipient's custom domain should be specified in the connector so only messages sent to their custom domain could be routed.
  • Please contact the recipient's admin to check the connectors and adjust them as necessary to allow email messages to be delivered from the sending domain.
  • More information on this error can be found in this Microsoft Article