Unable Bootstrap chef client on windows 7

Question

Following are the steps I have performed till now,

1. Installed chef-server and configured v11.0 on Ubuntu 10.04 LTS
2. Installed chefDK 0.17 on windows 7
3. Fetched certificate on workstation as well as on node from chef server
4. I have also updated hosts files on every machine

Now , while bootstrapping from workstation to install and register chef node on chef server I'm getting the following error

ERROR: Failed to authenticate to https://EVALCHEFLIN01.ecsemea.com:443 as ECSAdm
in with key C:/Users/ECSAdmin/.chef/admin.pem
Response:  Failed to authenticate as 'ECSAdmin'. Ensure that your node_name and
client key are correct.

What is that I'm doing wrong or missing while bootstrap?