Authorize.net CIM Active Merchant -- User authentication failed due to invalid authentication values
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I have deployed my live app with working payment gateway but I still need somewhere to test so created a account with sandbox.authorize.net and got a new api key.

Now when I try these details in development/staging I get - 

    User authentication failed due to invalid authentication values

When accessing authorize.net

Does active merchant work with sandbox.authorize.net? testing seems to work fine with a gateway set in test mode but not with a sandbox account.