I can't connect to RDS - Amazon QuickSight
Services or capabilities described in Amazon Web Services documentation might vary by Region. To see the differences applicable to the China Regions, see Getting Started with Amazon Web Services in China (PDF).

I can't connect to RDS

For details on troubleshooting connections to Amazon RDS, see Creating datasets from new database data sources.

You can also refer to the Amazon RDS documentation on troubleshooting connections, Cannot Connect to Amazon RDS DB Instance.