WorldPay AccessCheckoutSDK IOS "generateSession" gives "Identity is invalid" error

I am trying to integrate WorldPay's "AccessCheckoutSDK" in my IOS Application using Swift by following

https://developer.worldpay.com/docs/access-worldpay/checkout/ios/card-only

while generating session it give me "Identity is invalid" error . Here is the code i tried

 func initializedSDK() -> AccessCheckoutClient? {
    let accessCheckoutClient = try? 
   AccessCheckoutClientBuilder().accessBaseUrl(WORLDPAY_BASE_URL)
            .merchantId(WORLDPAY_MERCHANT_ID)
            .build()
    return accessCheckoutClient
}


func createCardDetails(CardNumber : String , CardExpiry : String , CardCVC : String) -> CardDetails? {
    let cardDetails = try? CardDetailsBuilder().pan(CardNumber)
        .expiryDate(CardExpiry)
        .cvc(CardCVC)
        .build()

    return cardDetails
}


func CreateSession(CardNumber : String , CardExpiry : String , CardCVC : String) {
    
  
    guard let accessCheckoutClient = initializedSDK() else {
       // not going here so accessCheckoutClient is initialized
        return
    }
    guard let cardDetails = createCardDetails(CardNumber: CardNumber, CardExpiry: CardExpiry, CardCVC: CardCVC) else {
        // Not going here , so card details are valid
        return
    }

    try? accessCheckoutClient.generateSessions(cardDetails: cardDetails, sessionTypes: [SessionType.card , .cvc ]) { result in
        DispatchQueue.main.async {
            switch result {
            case .success(let sessions):
                // The session is returned in a Dictionary[SessionType:String]
                //not going here
                let cardSession = sessions[SessionType.card]
                let cvcSession = sessions[SessionType.cvc]
                  

            case .failure(let error):
                // The error returned is of type AccessCheckoutError
                print("error \(error)")
                // It is going here and prints this error below
                
            }
        }
    }
 }
    

I am getting this error

AccessCheckoutError(errorName: "bodyDoesNotMatchSchema", message: "bodyDoesNotMatchSchema : The json body provided does not match the expected schema", validationErrors: [AccessCheckoutSDK.AccessCheckoutError.AccessCheckoutValidationError(errorName: "fieldHasInvalidValue", message: "Identity is invalid", jsonPath: "$.identity")])

WORLDPAY_BASE_URL = "https://try.access.worldpay.com/"

Note : I am using worldPay in testMode and didn't activated live mode yet and made sure that WORLDPAY_MERCHANT_ID is correct.

After all the research on worldPay , i decide to mail to worldPay support, After a brief chat with them and after they went through my worldPay account, this was their final reply :

"Your account status, "basic", "free tier" does not permit you to have access to this endpoint."

I decided to answer my own question so that if anyone have the same problem while integrating WorldPay with test Account, This would help them. I still think WorldPay developer can handle this scenario better by returning this exact string straightforward in the api response instead of throwing a 500 server error.

I welcome other answers and information on this post as well. If you have something informative about worldPay integration to IOS, please feel free to comment or answer this question.