Uncaught exception 'Coinbase_ApiException' with message 'Status code 401' I am using magento extension of coinbase bitcoin for my sandbox account.

But whenever I am trying to place an order on my store I am getting following error :

Fatal error:  Uncaught exception 'Coinbase_ApiException' with message 'Status code 401' .

Help me to resolve this.
HTTP status 401 is "Unauthorized", you likely have your credentials or keys configured incorrectly.