Can't see any response on connect

[cleverClosure]

Hi. Couldn't see any response from stomp client for some reason. Here is my code:

let headers = ["Authorization": "Bearer 24c8daa9-a941-45ad-8d8f-5e236be47b11"]

let client = STOMPClient(url: url, webSocketHeaders: headers, useHeartbeat: true)

client?.connect(withHeaders: headers, completionHandler: { (frame, error) in

    print("\(error?.localizedDescription)")

})

Any ideas why that might be the case?