HTTP requests being blocked by a previous one using Alamofire - ios

Question

I'm having some trouble with an HTTP request performed from our iOS app to our API. The problem with this request is that it usually takes 30-40s to complete. I don't need to handle the response for now, so I just need to fire it and forget about it. I don't know if the problem is in my code or in the server, that's why I'm asking here.
I'm using Alamofire and Swift 2.2 and all the other requests are working just fine. This is an screenshot from Charles proxy while I was trying to debug it: Charles screenshot
As you can see, the request that blocks the others is the refreshchannels. When that request fires (#6 and #25), the others are blocked and don't finish until the refreshchannels finishes.
Here is the code that triggers that request and also the APIManager that i've built on top of Alamofire:
// This is the method that gets called when the user enables the notifications in the AppDelegate class
func application(application: UIApplication, didRegisterForRemoteNotificationsWithDeviceToken deviceToken: NSData) {
// Recieve the APNSToken and handle it. I've removed it to make it shorter
// This sends a POST to our API to store some data
APIManager().registerForPushNotifications(parametersPush) { (result) in
switch result {
case .Success (let JSON):
// This is the slow call that blocks the other HTTP requests
APIManager().refreshChannels { _ in } // I don't need to handle the response for now
case .Failure: break
}
}
}
And the manager:
//This is my custom manager to handle all the networking inside my app
class APIManager {
typealias CompletionHandlerType = (Result) -> Void
enum Result {
case Success(AnyObject?)
case Failure(NSError)
}
let API_HEADERS = Helper.sharedInstance.getApiHeaders()
let API_DOMAIN = Helper.sharedInstance.getAPIDomain()
//MARK: Default response to a request
func defaultBehaviourForRequestResponse(response: Response<AnyObject, NSError>, completion: CompletionHandlerType) {
print("Time for the request \(response.request!.URL!): \(response.timeline.totalDuration) seconds.")
switch response.result {
case .Success (let JSON):
if let _ = JSON["error"]! {
let error = NSError(domain: "APIError", code: response.response!.statusCode, userInfo: JSON as? [NSObject : AnyObject])
completion(Result.Failure(error))
} else {
completion(Result.Success(JSON))
}
case .Failure (let error):
completion(Result.Failure(error))
}
}
func refreshChannels(completion: CompletionHandlerType) {
Alamofire.request(.PUT, "\(API_DOMAIN)v1/user/refreshchannels", headers: API_HEADERS).responseJSON { response in
self.defaultBehaviourForRequestResponse(response, completion: completion)
}
}
}
Any help will be appreciated. Have a nice day!