Hybrid Agent Validation fails after Extended Protection is enabled

Symptoms 

Consider the following scenario: 

• You install Microsoft Exchange Server 2019 Cumulative Update 12.

• You enable Extended Protection by running the Exchange Server Extended Protection script.

• You configure Hybrid Agent (Full or Modern) from the Exchange Control Panel (ECP).

• You check whether Hybrid Agent Validation is enabled.

In this scenario, Hybrid Agent Validation fails after you enable extended protection. 

Resolution 

To fix this issue, install Cumulative Update 13 or a later cumulative update for Exchange Server 2019.