Connecting to PostgresSQL hosted on AWS RDS?

Anonymous 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

In conclusion it's possible to connect to PostgresSQL on AWS RDS databases but it isn't easy