Open the operations console and navigate to the Key Management Service folder and State view to check if the service has been discovered and is in good state.
If the state is not good, use the Health Explorer to identify the issue.
If the service does not appear in the State view, install and activate it on the machine or install the proper KMS activation key.
Service Lacks Access To DNS Server
Open the Operations console, click the Monitoring button, open the Key Management Service folder, and then open Alerts view to determine if there are any ‘DNS RR Publishing Failed’ alerts related to that service.
If the mentioned alert exists, grant the KMS server the relevant permission to DNS server and you can also verify the DNS server is accessible from the KMS host.
After the KMS service completes DNS publishing, the alert will resolve automatically.
In addition, the machine state becomes critical, because it prevents the service from functioning as expected and the KMS service will not be able to publish itself in DNS. In this case, disable DNS publishing for this service from Console Tasks.
Machine Count Less Than Required Activation Limit
To make sure that there are enough machines requesting activation to sustain activation process, open the Operations console, click the Authoring button, click Management Pack Objects, and then click Monitors.
In Key Management Service, open Overrides for the KMS Low Activation Count monitor and update the Threshold value to the expected minimum machine count necessary to keep the activation process running.
Periodically check the Alerts view in the Key Management Service folder for low count alerts to ensure that activation is ongoing.
If the low activation count value is reached, the service will enter into a Warning state.
Missing Activation Requests
To monitor whether the network or any other accessibility problems prevent the client machines to access Key Management Service, periodically check the Alerts view in the Key Management Service folder for an Missing Activation Request alert.
The Missing Activation Request alert indicates there was no activation request for a known period of time for the KMS service.
Services with problems are listed in the Details View.
KMS License State Check
To verify whether the KMS service on a remote machine has been set up correctly with a valid license, open the Operations console, and open the Monitoring and Key Management Service folder.
In the State view, select the relevant KMS service from the State view, and in Console Tasks, run the KMS License State task.
To investigate stop notifications of Key Management Services, open the Operations console, click the Monitoring button, click Key Management Service, and then click State View.
View a list of services in Critical State in the Health Explorer.
To fix the issue, run the Console Task named KMS Start Service.