200 - success
100 - bad username or password
101 - NexusMerchants is Inactivated [check your emails for credit card update requests and contact us]  
102 - Merchant not setup properly
103 - Action not supported
104 - Payment Gateway ErroR
105 - No merchant found with this name
106 - Nexus Merchants: Error during updating database.
107 - Payment Gateway : *ERROR MESSAGE (This message comes dynamically based on merchant)*
108 - Transaction has been failed
109 - Transaction does not exist in the system
110 - Refund amount does not match in system
111 - This user have not access to this transaction