I am using C# - SDK code for Credit Card transaction. It is always giving "The transaction was unsuccessfull". But it working fine with SANDBOX (with sandbox credentials)

The only change I made was replace

ApiOperationBase<ANetApiRequest, ANetApiResponse>.RunEnvironment = AuthorizeNet.Environment.SANDBOX;

with

ApiOperationBase<ANetApiRequest, ANetApiResponse>.RunEnvironment = AuthorizeNet.Environment.PRODUCTION;

Note: I am using the production API Login ID and Transaction Key for production mode.

Please help, my customer is very annoyed with it.