This is the error message that FedEx typically returns when an account has not yet been enabled for API dispatch. FedEx requires that each new account set up with them be enabled.
 

Enable Pickup And/Or Shipping(BOL) for LTL
Once you have completed your account set-up and have confirmed rates are processing successfully you will need to request that your FedEx account be enable for Pickup and/or BOL.

1. After obtaining you production credentials and completing the Project profiles, Call the FedEx support line at1.877.339.2774
2. Identify yourself as a Project 44 customer
3. Ask the agent to access KB article 18598
4. Provide the agent your name
5. You should be asked what services need to be enabled. Reply with either Pickup or Shipping, or both.
6. Provide the agent with your credential information and the services will be enabled.​​​​​​​​​​​​​​
   1. Account Number:
   2. Meter Number
   3. Authentication Key