Unable to know the reason for the response "This tracking number cannot be found. Please check the number or contact the sender" - response

Question

I am getting a response "This tracking number cannot be found. Please check the number or contact the sender.", which is present in this object.
when I execute a php code to get tracking-id(781193603730) status data got from Fedex. But when I try to check the status of tracking id by loging into their portal I am able to get response. I need help on this, please help. Response object =>
stdClass Object
(
[HighestSeverity] => SUCCESS
[Notifications] => stdClass Object
(
[Severity] => SUCCESS
[Source] => trck
[Code] => 0
[Message] => Request was successfully processed.
[LocalizedMessage] => Request was successfully processed.
)
[TransactionDetail] => stdClass Object
(
[CustomerTransactionId] => *** Track Request using PHP ***
)
[Version] => stdClass Object
(
[ServiceId] => trck
[Major] => 16
[Intermediate] => 0
[Minor] => 0
)
[CompletedTrackDetails] => stdClass Object
(
[HighestSeverity] => SUCCESS
[Notifications] => stdClass Object
(
[Severity] => SUCCESS
[Source] => trck
[Code] => 0
[Message] => Request was successfully processed.
[LocalizedMessage] => Request was successfully processed.
)
[DuplicateWaybill] =>
[MoreData] =>
[TrackDetailsCount] => 0
[TrackDetails] => stdClass Object
(
[Notification] => stdClass Object
(
[Severity] => ERROR
[Source] => trck
[Code] => 9040
[Message] => This tracking number cannot be found. Please check the number or contact the sender.
[LocalizedMessage] => This tracking number cannot be found. Please check the number or contact the sender.
)
[TrackingNumber] => 781193603730
[StatusDetail] => stdClass Object
(
[Location] => stdClass Object
(
[Residential] =>
)
)
[PackageSequenceNumber] => 0
[PackageCount] => 0
[DeliveryAttempts] => 0
[TotalUniqueAddressCountInConsolidation] => 0
[DeliveryOptionEligibilityDetails] => Array
(
[0] => stdClass Object
(
[Option] => INDIRECT_SIGNATURE_RELEASE
[Eligibility] => INELIGIBLE
)
[1] => stdClass Object
(
[Option] => REDIRECT_TO_HOLD_AT_LOCATION
[Eligibility] => INELIGIBLE
)
[2] => stdClass Object
(
[Option] => REROUTE
[Eligibility] => INELIGIBLE
)
[3] => stdClass Object
(
[Option] => RESCHEDULE
[Eligibility] => INELIGIBLE
)
)
)
)
)

Answer 1

I found that the fedex tracking id that I was testing was real, and the credentials that I was using for fedex tracking api were of test/sandbox type not production.