When you try to connect to Amazon Redshift from Exploratory, you might see an error message that looks like this.
Could not connect to server: Connection timed out. Is the server running on host '<endpoint>' and accepting TCP/IP connections on port '<port>' ?
If you hit this, please check the below Amazon AWS document and follow the Possible solutions section.
https://docs.aws.amazon.com/redshift/latest/mgmt/connecting-refusal-failure-issues.html