static class InitTask extends AsyncTask<Void, Integer, Integer> {

         ...

		@Override
		protected Integer doInBackground (Void... arg0) {
			WifiManager wifi = (WifiManager)context.getSystemService(Context.WIFI_SERVICE);
			WifiConfiguration conf = new WifiConfiguration();

			conf.SSID = "\"" + site.getWifiSSID() + "\"";   // Please note the quotes. String should contain ssid in quotes
			
			// Only support WPA
			conf.preSharedKey = "\"" + site.getwifiWPAKey() + "\"";
			
			int wifiState = wifi.getWifiState();
			Boolean enabled = wifi.isWifiEnabled();
			
			if ((site.getSavedDeviceWifiState() != WifiManager.WIFI_STATE_ENABLED) &&
					(site.getSavedDeviceWifiState() != WifiManager.WIFI_STATE_ENABLING)) {
				wifi.setWifiEnabled(true);
			}
			
			wifi.addNetwork(conf);

			List<WifiConfiguration> list = wifi.getConfiguredNetworks();
			for( WifiConfiguration i : list ) {
			    if(i.SSID != null && (i.SSID.equals("\"" + site.getWifiSSID() + "\"") == false)) {
			    
			         wifi.disconnect();
			         wifi.enableNetwork(conf.networkId, true);
			         wifi.reconnect();               
			         
			         break;
		    	     }
			 }
			 String verif = site.getWifiSSID();
		}
		
                // If I put a breakpoint here, the following code runs without any problem
		int responseCode = 0; 
		try {
			int i = 0;
			url = new URL(site.getDescriptionFileUrl());

			// Création d'une connection HTTP à une URL
			URLConnection connection = url.openConnection();
			HttpURLConnection httpConnection = (HttpURLConnection)connection;

                        // Next Call immediately throws a ConnectException
			responseCode = httpConnection.getResponseCode();

			if (responseCode == HttpURLConnection.HTTP_OK) {
                            ...
                       }
		}
		catch (MalformedURLException e) {
			Log.d("2ndGuide", "Malformed URL Exception." + e);
		} 
		catch (IOException e) {
			Log.d("2ndGuide", "IO Exception." + e);
		}
		Log.d("2ndGuide", mActivity.getResources().getString(R.string.label_messageAlertCnfBadUrl));
		return -6;
	}