The connection property set was missing a required property or the property value was unrecognized. Instance not available on server

Error Message

Attempts to validate an ArcGIS Data Store relational data store fail, and return the following error messages in the ArcGIS Server Administrator Directory logs:

Error:   
The connection property set was missing a required property or the property value was unrecognized. Instance not available on server

Error:   
Failed to create the service.: ERROR: unable to connect to the database: <MachineName>. Reason: Instance not available on server

Cause

Missing or inaccurate information in the ArcGIS Data Store configuration file causes the validation to fail as ArcGIS Enterprise is directed to a different or non-existent data store in the deployment.

Solution or Workaround

Unregister and re-register the data store using the ArcGIS Data Store command utilities to reconfigure the data store. After the configuration is completed, proceed to validate the data store.