How can we install Chef plugin from ElectricFlow Community Edition?

How can we install Chef plugin from ElectricFlow Community Edition?

I followed this procedure

1. Go to Administration > Plugins to open the Plugin Manager.
2. Find the EC-Chef row.
3. Click Configure to open the Chef Configurations page.
4. Click Create Configuration
5. Create a Chef configuration by entering the following information and clicking OK.

What we should specify in the section for:

USERNAME:

PRIVATE KEY:

I have given as username of (which we will create at the time of chef server configuration ) and private key of that user (EG : ncode.pem)

I tried with machine key also but, both methods are showing an error:

"Error occurred during configuration creation: Aborting job after reaching timeout.  Job successfully aborted"