Running the ArcGIS Data Store describedatastore utility returns the following error message:
Error encountered: No valid connection to ArcGIS Data Store configuration store established.
Caused by: Connection to localhost:9876 refused. Check that the hostname and port are correct and that the postmaster is accepting TCP/IP connections.
There is no postmaster.pid file and the ArcGIS Data Store Windows service account has sufficient permissions to modify or delete a .pid file. So, the issue is not the one discussed in the below article.
https://support.esri.com/en-us/knowledge-base/error-error-encountered-no-valid-connection-to-configur-000025655