Troubleshooting Connection Issues in Amazon Redshift
If you have issues with connecting to your cluster from a SQL client tool, there are several things that you can check to narrow down the problem. If you are using SSL or server certificates, first remove this complexity while you troubleshoot the connection issue. Then add this back when you have found a solution. For more information, see Configure Security Options for Connections.
The following section has some example error messages and possible solutions for connection issues. Because different SQL client tools provide different error messages, this is not a complete list, but should be a good starting point for troubleshooting issues.