An exception occurred: Please install Npgsql version 4.0.10.0 or earlier.

You need a gateway, and you need to install the indicated PostGreSQL driver on the gateway.  There is a well documented bug that the gateway installer is missing that driver.  You need to borrow the driver files from your desktop setup and paste them into the ADO folder on the gateway.

Hi luqui_maps ,

Please refer to the following steps: 

the PostgresSQL connector doesn't work out of the box, you need to do quite a few things first

1. Install Npgsql which allows .NET access to PostgresSQL.  I installed it using the Pakagae Manager Console in Visual Studio; detailed instructions are here: https://www.nuget.org/packages/Npgsql/

You need to connect over SSL to AWS which isn't setup by default (on my Windows 10 machine anway)

2. Download the AWS public key from here https://s3.amazonaws.com/rds-downloads/rds-combined-ca-bundle.pem

3. Convert that to a certificate using https://www.sslshopper.com/ssl-converter.html (convert to PKCS#7/P7B)

4. Import that certificate to the Trusted Room Certificate described here http://www.cs.virginia.edu/~gsw2c/GridToolsDir/Documentation/ImportTrustedCertificates.htm

5. Test access from Power BI desktop using the PostgresSQL connector and it should work

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