This is a generic Cybersource error that can be caused by a number of items. Below are a few troubleshooting measures to take in the product, to confirm the account is set to active in the product. 
  • Verify the Cybersource merchant account is set up correctly, and with the proper credentials
  • Confirm the Merchant Account is not inactive or set to Demo mode
  • Create a new Cybersource merchant account with the same credentials
  • Request a new system key from Cybersource and creating a new merchant account

Additional Information:
Contact Cybersource support.