If when you use the Network troubleshooter or any other troubleshooter you receive this error it means that it found issues but could not resolve them because the Diagnostics Policy Service is not running. This service however can be re-enabled quite easily through Command Prompt. Let’s get going.
This is a uncommon error on Windows since the System Event Notification Service is a service that is self regulating, thus it should always be active on your system and this error should not appear. However if it does appear it’s quite simple to solve by using Services.msc.