Open file eway_payment.php

Look for line (approx line number: 60)
header("Location:$Success_Page?osCsid=$response_tr xn_Option1&order_id=$response_trxn_number");

change it to
header("Location:$Success_Page?osCsid=$response_tr xn_Option1&order_id=$response_trxn_number&authcode =$response_trxn_AuthCode&status=$response_trxn_sta tus");

This fix is required to make eway payment module to work otherwise you will be getting the error "Credit Card Error!".

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