In this tutorial, we will see how to avoid CCAvenue Error Code 10002 Merchant Authentication Failed ! This CCAvenue Error Code 10002 problem is a usual problem that occurs after connecting our application to the CCAvenue payment gateway. But, it is not a big issue to solve. This problem can be solved as easily as changing few lines code. CCAvenue is one of the leading online payment gateway service provider similar to other popular providers PayPal, Citrus, PayUMoney etc. Easy integration is an advantage of CCAvenue payment gateway. How to avoid the CCAvenue Error Code 10002 Merchant Authentication Failed ! This error occurs when we don't use right options suggested by CCAvenue while integrating them into the application. Following are few reasons of this error: Incorrect Merchant ID Incorrect Working Key Incorrect Access Key URL of the registered website User mostly do the mistake on using above four option while integrating CCAvenue in the application,