Error Connecting To Postgresql Via Proxy After Updating To Tableau Desktop 2020.4

Issue

When attempting to connect to a PostgreSQL database in Tableau Desktop 2020.4 or newer, in an environment where a proxy server is enabled, the following error occurs:

Unable to connect to the server. Check that the server is running and that you have access privileges to the requested database.
Error Code: BC42EF73
The connection attempt failed.
Unable to connect to the PostgreSQL server '<server-address>'. Check that the server is running and that you have access privileges to the requested database.

No error occurs in earlier versions of Tableau Desktop.

Environment

Tableau Desktop 2020.4 or newer
PostgreSQL

Resolution

Option 1

If your proxy server doesn't support SOCKS, Disable "Use the same proxy for all protocols" and make sure Socks protocol fields are blank.
User-added image

Option 2

If the database address is added to the exceptions list for the proxy server, do not use wildcards - specify the full IP address or FQDN.

Option 3

Connect to the database using ODBC instead of JDBC. Remove the PostgreSQL JDBC driver from 'C:\Program Files\Tableau\Drivers' and Tableau will fallback to using ODBC with the native PostgreSQL connector.

Cause

Starting in version 2020.4, Tableau uses JDBC by default when connecting to PostgreSQL instead of ODBC. JDBC drivers can have trouble interpreting proxy settings which leads to a connection failure.