When configuring a standby data store in a high availability ArcGIS Enterprise deployment, the data store configuration process fails, returning the following error message:
Error: GIS Server may not be running. Please check server URL or make sure that service is running.
This issue occurs if the primary data store and standby data store is unable to communicate with each other over the network.
To resolve this issue, ensure both the primary and standby data store are able to communicate over the network that the high availability ArcGIS Enterprise deployment is using. The primary data store must be able to replicate and communicate its contents and configuration to the standby data store.
For example, depending on the organization, group policies may dictate individual machine network and firewall settings. This may prevent communication between various ArcGIS Enterprise components. Refer to ArcGIS Help: Best practices for configuring a secure environment for some best practices on network security settings.