Root Cause

• Live account used in test environment: The customer attempted to use a real bank account while the system was operating in test mode.
• Environment mismatch: Initiating transactions in test mode but using production/live bank account credentials.
• Incorrect account setup for testing: Sandbox or test account details were not used as required in the testing environment.
• Gateway enforcement: The payment gateway prevents real bank account details from being used in a non-production environment for security and compliance reasons.

Troubleshooting and Solutions

• Use sandbox or test bank account details while operating in test mode.
• Verify that the payment environment is correctly set to production before using live bank account details.
• Clearly separate and document the usage of test and live account environments to avoid confusion.
• Retry the transaction only after ensuring that the correct account type is used for the current environment.
• Review payment gateway documentation for guidelines on using appropriate test data in the sandbox environment.