Google Geocode API deny the request - NodeJS

I want a geocode a street address in NodeJS, but the the google API deny the request, because of the IP address. I have dedicated IP address on my server, I generated API key used this IP address. My request looks like this:

https.get('http://ift.tt/1DSDD4t', function(response){...........});

I registered my currently public IP address of my computer just for to try the API and if I send a request from my computer it is working fine.

I found the following instruction on google developer site:"Every API request is generated by software running on a machine that you control. Per-user limits will be enforced using the address found in each request's userIp parameter, (if specified). If the userIp parameter is missing, your machine's IP address will be used instead."

Does it mean that I can add userIp parameter like this?:

https.get('http://ift.tt/1CXTLOd', function(response){...........});

I tried this on as well, but still not working. Has anyone an idea what I doing wrong?