Problem with Swift API Gateway key authorizatiion Ask

Question

I tried adding a key for my API but there's a problem with implementing it into my application's code.
I keep on getting a message = Forbidden;

I tried different methods but none of them seems to be working.
I can't really figure out the problem here!

if let jsonData = try? JSONSerialization.data(withJSONObject: dict, options: .prettyPrinted) {

        let url = NSURL(string: "\(APIAddress)")!
        let request = NSMutableURLRequest(url: url as URL)

        request.httpMethod = "PATCH"
        request.addValue("application/json", forHTTPHeaderField: "Content-Type")
        request.addValue("\(APIKey)", forHTTPHeaderField: "Authorization")
        request.httpBody = jsonData

        let task = URLSession.shared.dataTask(with: request as URLRequest) { data, response, error in
            if error != nil {
                print(error?.localizedDescription as Any)
                return
            }

            do {
                let json = try JSONSerialization.jsonObject(with: data!, options: .mutableContainers) as? NSDictionary

                if let parseJSON = json {
                    let resultValue = parseJSON["success"]
                    print("result: \(String(describing: resultValue))")
                    print(parseJSON)
                }
            } catch let error as NSError {
                print(error)
            }
        }
        task.resume()
    }

Please note the method was working before activating the API key on API Gateway