Redshift could not send SSL negotiation packet: Resource temporarily unavailable

Hi ,

Issue Summary

I’m hosting the Redash in AWS EC2 private subnet, we had setup a connection to Redshift, it was working well, but suddenly it’s not working this week, we didn’t update anything, and the security group is setting up correctly(as redshift allowing Redash ec2 security group as in-bound rule, we didn’t update anything).

  • The Redshift connection itself does not have any issue, as I can connect it from local through a bastion host.

  • There is no issue to connect to other resources like Postgresql DB in Redash

Technical details:

Here is the running docker images

Kindly help to give some ideas about where the issue could be?

Thanks and regards

Welcome to the forum!

I’ve seen this error message literally hundreds of times. It has always been a firewall issue. Traffic is not making it between your Redash query runners and the redshift instance.

It’s not really something we can debug for you on the forum. But the fact that you haven’t changed anything recently with your Redash configuration makes it more likely that something changed in your security groups.

Thanks Jesse, yes, it was really due to firewall issue, for anyone facing similier issue, my case like this,


  • Redshift and Redash EC2 in the same VPC
  • Redshift in public subnet, EC2 in private subnet
  • Redshift has EC2 as inbound rule in security group

I send a ticket to AWS support, they told me the Redash ec2 resolved the Redshift host as public IP, it requires to go from NAT gateway to access redshift, after I added the NAT gateway IP in the Redshift inbound rule, the issue was solved, I’m still checking with AWS team why the issue suddenly happen(seems due to a redshift patch).