Dxdumpdb failed with the following error message.
Datastore 'C:\Program Files\CA\Directory\dxserver\data\<dsa name>.db' cannot be accessed
It failed with the same error message when you use the -z option
Datastore 'C:\Program Files\CA\Directory\dxserver\data\<dsa name>.zdb' cannot be accessed
The db (zdb) file exists in dxserver\data directory.
This is a known issue which is recorded in bug DE440130.
The problem only happens on Windows platform when dxgrid-db-size is set to more than 4000 (4GB).
CA Directory 12.x, 14.0, 14.1, 14.1 CR1 on Windows platform
This issue has been permanently fixed in Service Pack 1 for 14.1 which was released in June of 2020 and is available from the Broadcom Support Portals Download center.