While opening the report with Spotfire Analyst on a PC with ODBC drivers v9.6.3, we obtain the following error : 

The query is not supported in the external data source.
External error:
ERROR [25P02] ERROR: current transaction is aborted, commands ignored until end of transaction block;
Error while fetching the next result

All Supported OS

This is a bug in the driver that was fixed in version 09.06.0400 (for a crash in some scenarios there):
Fix a crash bug in SQLBulkOperations() under use_declare/fetch off mode.
(As can be seen here: https://odbc.postgresql.org/docs/release.html)

There are two solutions to solve this driver issue:

(1) Upgrade the ODBC driver to above mentioned version(09.06.0400) at least or to the latest version(recommended) to resolve this issue.
Or
(2) From Spotfire 11.4 HF-004 onwards, Spotfire has added a preference to tackle this issue,
- It can be located under "Connectors > PostgreSql > UseDeclareFetch" > set to 'False' (screenshot attached)
- Restart the Spotfire Client to test the behavior.

This article describes why Postgres data source throws "The query is not supported in the external data source" error when accessed via Connectors

External:

• https://odbc.postgresql.org/docs/release.html