This is by design with Exchange 2016 on-prem deployments. This is from the Exchange 2016 release notes.
Notifications Broker service stops after 30 seconds When you start your Exchange server, you might notice the Notifications Brokerservice start and then stop after approximately 30 seconds. If you attempt to start the service manually, it will successfully start and then stop, again after approximately 30 seconds. No errors or warnings are included in the Event log.
This behavior is expected in on-premises deployments of Exchange 2016. The Notifications Broker service performs a configuration check on each time the server starts. If there is nothing for the Notifications Broker service to do, it stops automatically until the next time the server is restarted.
As the error is very annoying and can look problematic this service check can be disabled in Server manager by selecting the drop down box next to 'services' find 'Microsoft Exchange Notifications Broker'
