I'M Testing Login Authentication in Swift Using Firebase and Getting Errors Get Output Frames Failed, State 8196

SSL_ERROR_SSL(1): operation failed within the library

Deadlock

I assume spotifyRequest will be called on the main thread.

So if the main thread reaches the line

group.wait()

and this line of responseJSON completionHandler was not called yet:

group.leave()

then the main thread is blocked due to the call of group.wait() above.
Due to the blocked main thread group.leave() can't be called. Classical deadlock.

Verfication

Setting a breakpoint to the line

if let safeStatus = status {

shows that this line is never called.

Minimal Example that is running

As a starting point here the code for a minimal example that delivers a result.

import UIKit
import Alamofire

class ViewController: UIViewController {

    override func viewDidLoad() {
        super.viewDidLoad()

        self.contactSpotify {
            print ("result: \(String(describing: $0)) error: \(String(describing: $1))")
        }
    }

    func contactSpotify(completion: @escaping ([String: Any]?, Error?) -> Void) {
        let url = URL(string: "https://accounts.spotify.com/api/token")!
        Alamofire.request(url,
                          method: .post,
                          parameters: ["grant_type": "refresh_token",
                                       "client_id": "<someClientId>",
                                       "refresh_token": "<someRefreshToken>",
                                       "client_secret": "<someClientSecret>"])
            .validate()
            .responseJSON { response in
                guard response.result.isSuccess else {
                    completion(nil, response.result.error)
                    return
                }

                completion(response.result.value as? [String: Any], nil)
        }
    }

}

This gives as output in the console:

result: Optional(["access_token": XXX, "scope": user-read-email user-read-private, "token_type": Bearer, "expires_in": 3600]) error: nil

see Screenshot:

ATS Settings in info.plist

Spotify offers a valid TLS certificate chain on their server. So there is no need for ATS settings in info.plist.

SSL Warnings in Console

I get the same SSL warnings in the console when I run the application on an iOS 12 simulator like you. Nonetheless the connection is established and the request delivers data. Perhaps this is gone in one of the next betas.

How to fix [BoringSSL] nw_protocol_boringssl_error(1584), Lower protocol stack error: 54 in Xcode Project v-10.1

Those error messages are just network debugging stuff you can safely ignore. On the other hand, the screen going black is just the normal iOS behaviour, and you can turn it off with:

UIApplication.shared.isIdleTimerDisabled = true

This will prevent the screen from dimming and turning off after inactivity periods. Set the value back to false as soon as the functionality is not needed anymore, otherwise your users will get really upset about their battery life.

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