If you are working with Microsoft Exchange 2016, On-Prem, you weill find a new service named, Microsoft Exchange Notifications Broker. The Notifications Broker service is set to start AUTOMATICALLY by default and if you start it manually you will notice it stops after 30 seconds.
What Is The Microsoft Exchange Notifications Broker Service?
The Microsoft Exchange Notifications Broker is was introduced in Exchange 2016 (and dropped from Exchange 2019) to:
Provide Exchange notifications to local and remote Exchange processes. SOURCE
It is a required service in Exchange 2016 and is dependent on both Microsoft Exchange Active Directory Topology Service and the Net.TCP Port Sharing Service.
Why Does the Microsoft Exchange Notifications Broker Service Stop Running?
The Exchange Notifications Broker service only runs for 30 seconds and then stops automatically by design because it is only checking the servers configuration at startup. To save resources it turns itself off after the checks are complete.
How To Disable Notification Broker Service Alerts in Server Manager?