iOS: Unable to convert Json String to Array in swift?

In my project I want to convert Json String from server to Array but Unable to convert, But when I hard code(Directly gave the particular json string) the json string means that will be convert. Please help me to find the issue..

Here I gave the code what i am tried.

var params = NSMutableDictionary()
    params = [
        "inspectionLogId": inspectionLogIdStr
    ]
    let manager = AFHTTPSessionManager()
    manager.requestSerializer = AFJSONRequestSerializer()
    manager.responseSerializer = AFHTTPResponseSerializer()
    manager.responseSerializer.acceptableContentTypes = NSSet(array: ["text/plain", "text/html", "application/json"]) as Set<NSObject> as Set<NSObject>! as! Set<String>?
    manager.requestSerializer.setValue("", forHTTPHeaderField: "apptoken")
    manager.requestSerializer.setValue(strAppToken, forHTTPHeaderField: "token")
    let urlString:NSString = NSString(format: "%@%@", ApiConstantFile().baseUrlProperty,ApiConstantFile().getTemplateDataUrl)
    print(urlString)
    manager.get(urlString as String, parameters: params, progress: nil, success: {
        (operation, responseObject) in
        self.stopAnimation()

        let jsonstring = String(data: responseObject! as! Data, encoding: String.Encoding.utf8)
        print("jsonstring is:, \(jsonstring!)")

        let data = jsonstring!.data(using: .utf8)!
        print(data)
        do {
            if (try JSONSerialization.jsonObject(with: data, options : .allowFragments) as? [Dictionary<String,Any>]) != nil {
                let jsonArray = try JSONSerialization.jsonObject(with: data, options : .allowFragments) as! [Dictionary<String,Any>]
                print(jsonArray)
            } else {
                print("bad json")
            }
        } catch {
            print(error)
        }

    }, failure: {
        (operation, error) in
        self.stopAnimation()
        print(error)
        self.alert(message: error.localizedDescription)
    })

when I print the json string means they show to string:

"[{\"propertyId\":\"1\",\"inspectionTemplateId\":1118,\"value\":[{\"widgetControllerId\":141,\"value\":\"Flood Summary Name\"},{\"widgetControllerId\":142,\"value\":\"Did the property flood?\"},{\"widgetControllerId\":143,\"value\":\"no\"}]}]"

But when I directly gives the string means it will convert to array.

let jsonstring = "[{\"propertyId\":\"1\",\"inspectionTemplateId\":1118,\"value\":[{\"widgetControllerId\":141,\"value\":\"Flood Summary Name\"},{\"widgetControllerId\":142,\"value\":\"Did the property flood?\"},{\"widgetControllerId\":143,\"value\":\"no\"}]}]"