Problem: you just created a new instance, and even though you told it to be publicly available, you can’t connect to it using the provided endpoint….
Solution: you need to explicitly add your current ip address to the security group you are using. Their default security group is miss-leading: even though it says it will accept all traffic from everywhere, it doesn’t (sad panda). Once you add a new security group and attach it to the redshift instance, you will be fine fine fine.
Source of the solution: the infamous stackoverflow: