The following NullReferenceException is shown when you run the Test-FederationTrust cmdlet in Microsoft Exchange Server 2019 or Exchange Server 2016. This issue occurs when a new certificate for the federation trust is enabled, and the previous certificate has expired.

WARNING: An unexpected error has occurred and a Watson dump is being generated: Object reference not set to an instance

of an object.

Object reference not set to an instance of an object.

+ CategoryInfo          : NotSpecified: (:) [Test-FederationTrust], NullReferenceException

+ FullyQualifiedErrorId : System.NullReferenceException,Microsoft.Exchange.Management.SystemConfigurationTasks.TestFederationTrust


This issue occurs because a thumbprint property is still printed if null is assigned to orgPrevPrivCertificate when calling this.GetOrganizationCertificate in this situation.


To fix this issue, install one of the following updates:

For Exchange Server 2019, install the Cumulative Update 7 for Exchange Server 2019 or a later cumulative update for Exchange Server 2019.​
For Exchange Server 2016, install the Cumulative Update 18 for Exchange Server 2016 or a later cumulative update for Exchange Server 2016.


Learn about the  terminology that Microsoft uses to describe software updates.

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