Apollo Swift iOS Subscription Error

Getting Below error message when trying to establish an connection with subscription

ApolloWebSocket.WebSocket.WSError.ErrorType.writeTimeoutError, message: "Timed out waiting for the socket to be ready for a write", code: 0)"

using below code

Using Package 0.53.0 of Apollo 
added  below Libraries as shown in screen shot 

import Apollo
import ApolloWebSocket

class Network {
    static let shared = Network()
    class NetworkInterceptorProvider: DefaultInterceptorProvider {
        override func interceptors<Operation>(for operation: Operation) -> [ApolloInterceptor] where Operation : GraphQLOperation {
            var interceptors = super.interceptors(for: operation)
            interceptors.insert(AuthorizationInterceptor(), at: 0)
            return interceptors
    class AuthorizationInterceptor: ApolloInterceptor {
        func interceptAsync<Operation>(
            chain: RequestChain,
            request: HTTPRequest<Operation>,
            response: HTTPResponse<Operation>?,
            completion: @escaping (Result<GraphQLResult<Operation.Data>, Error>) -> Void
        ) where Operation : GraphQLOperation {
            // TODO

    private(set) lazy var apollo: ApolloClient = {
        let client = URLSessionClient()
        let cache = InMemoryNormalizedCache()
        let store = ApolloStore(cache: cache)
        let provider = NetworkInterceptorProvider(client: client, store: store)
        let url = URL(string: "http://apollo-fullstack-tutorial.herokuapp.com/graphql")!
        let transport = RequestChainNetworkTransport(interceptorProvider: provider, endpointURL: url)
        let webSocket = WebSocket(
            url: URL(string: "ws://apollo-fullstack-tutorial.herokuapp.com/graphql")!,
            protocol: .graphql_ws
        let webSocketTransport = WebSocketTransport(websocket: webSocket)
        let splitTransport = SplitNetworkTransport(
            uploadingNetworkTransport: transport,
            webSocketNetworkTransport: webSocketTransport
        return ApolloClient(networkTransport: splitTransport, store: store)

In viewcontroller methods is called in viewDidLoad()

  var activeSubscription: Cancellable?
    func startSubscription() {
        activeSubscription = Network.shared.apollo.subscribe(subscription: TripsBookedSubscription()) { [weak self] result in
            guard let self = self else {

            switch result {
            case .success(let graphQLResult):
                if let tripsBooked = graphQLResult.data?.tripsBooked {

                if let errors = graphQLResult.errors {
            case .failure(let error):

Used below URL for testing the subscription

subscription syntex

subscription tripsBooked

++ @Priya_Soni

I think you need to use the secure versions of those protocols. Try https://apollo-fullstack-tutorial.herokuapp.com/graphql and wss://apollo-fullstack-tutorial.herokuapp.com/graphql.