NEHotspotConfigurationManager error problem

I found a problem when i try to connect a non-existent wifi, this is my code:

let configuration = NEHotspotConfiguration.init(ssid: "wifi-name")
 NEHotspotConfigurationManager.shared.apply(configuration) { [unowned self] (error) in
       print("NEHotspotConfigurationManager.error: \(error)")
   }

if the wifi dosen't exist, i see and dialog with "impossible to connect network "wifi-nam"", but the error in the NEHotspotConfigurationManager is nil, so how can control if a specific ssid wifi exists?

Thank