M1 – Invalid merchant id
M2 – Authentication failed (wrong password or digest or signature)
SE – System error (message contains error id, system or configuration error to be investigated)
XE – Invalid XML request not parseable or does not validate
I0 – Invalid or unsupported request
I1 – Message contains invalid data item or missing required item
I2 – Message contains invalid installment parameters
I3 – Message contains invalid recurring parameters
I4 – Message contains invalid or mismatching card data
I5 – Message contains invalid expiration date card data
I6 – Selected payment method does is not supported or not matching the payment card
O1 – Operation is not allowed because logic is violated or wrong amounts
O2 – Original transaction is not found to perform operation. (May be also filled in case of status is REFUSED with acquirer network supplied ISO response code)