I'm trying to bootstrap a new chef node by running: knife bootstrap <server ip> -x lewis -N gitlab --sudo But I get the following output: [Mon, 03 Sep 2012 14:45:17 +0000] INFO: *** Chef 10.12.0 *** [Mon, 03 Sep 2012 14:45:17 +0000] INFO: Client key /etc/chef/client.pem is not present - registering [Mon, 03 Sep 2012 14:45:17 +0000] INFO: HTTP Request Returned 401 Unauthorized: Failed to authenticate. Ensure that your client key is valid. [Mon, 03 Sep 2012 14:45:17 +0000] FATAL: Stacktrace dumped to /var/chef/cache/chef-stacktrace.out [Mon, 03 Sep 2012 14:45:17 +0000] FATAL: Net::HTTPServerException: 401 "Unauthorized" My chef server is running Ubuntu 12.04 x32 and the machine I'm trying to bootstrap is running CentOS 6.3 x64 Any idea what's going wrong?