So I took a look at it, and I don’t have more information than what AWS is giving us with “Instances failed to join the kubernetes cluster”.
This sometimes happens because of the instance type selected, or because there is not enough machine available of this instance type in given region.
But on our side, we can’t do much. I recommend you to either try to change the instance type and trigger a re-deployment, or create a ticket to AWS support in order to ask them to investigate the issue.
I am deleting all AWS ressources for this cluster for you in the meantime.