I am getting this error:
stdClass Object
(
[Severity] => ERROR
[Source] => crs
[Code] => 959
[Message] => The account number entered for FEDEX_FREIGHT could not be validated.
[LocalizedMessage] => The account number entered for FEDEX_FREIGHT could not be validated.
[MessageParameters] => stdClass Object
(
[Id] => ACCOUNT_NUMBER_TYPE
[Value] => FEDEX_FREIGHT
)

)

I verified my Freight ID number with FedEx so I know my Freight ID is correct.