What causes Metadata service to be very slow?

Hello, on a fresh Grizzly deployment, our metadata service is very slow : $ time curl http://169.254.169.254/2009-04-04/meta-data/instance-id i-0000000d real 0m16.295s user 0m0.012s sys 0m0.000s This causes a very long boot time for instances (like 4-5 minutes). At the moment we are not injecting any file or script, neither we are using cloud-init. Nothing in the logs seems to explain this issue. What could be the cause of such long delays? Thanks in advance, Cheers