Root Cause

• Invalid or missing authentication credentials: The merchant’s authentication credentials (API keys, tokens, or passwords) are incorrect or have expired.
• Revoked or expired API keys: The credentials used to access the payment gateway are no longer valid.
• Incomplete integration setup: Authentication details were not properly configured in the payment system.
• Security policy enforcement: The payment gateway is enforcing updated authentication protocols that have not been implemented.

Troubleshooting and Solutions

• Verify and update the authentication credentials used to connect with the payment gateway.
• Regenerate API keys or tokens if they have expired or been revoked, and update them in the system.
• Retry the transaction after ensuring the correct and active authentication details are in place.
• Contact the payment gateway support team if authentication issues persist despite updating the credentials.
• Implement monitoring to proactively check for credential expirations and prevent future authentication failures.