diff --git a/devops-service/providers/ec2.rb b/devops-service/providers/ec2.rb
index 42f5d8b..0b0b2de 100644
--- a/devops-service/providers/ec2.rb
+++ b/devops-service/providers/ec2.rb
@@ -254,7 +254,7 @@ module Provider
     end
 
     def stack_servers(stack)
-      stack_resources(stack).map{|r| compute.servers.get(r.physical_resource_id)}
+      stack_resources(stack).map{|r| compute.servers.get(r['physical_resource_id'])}
     end
 
     def create_default_stack_name s