android 33 can't access specific wifi network

Question

I have an IOT device that, at startup, sets up a local access point that can accept an HTTP request to provide connection details for an access point that is connected to the internet.

I am writing an Android app that connects to the local access point then sends the HTTP request.

If I manually establish a connection to the local access point and then run the code to send the HTTP request, it works fine. If I create the connection to the local access point from the app, this succeeds (I can see this on the IOT device), but when I try to send the HTTP request I get an ENONET error.

Here is the code to connect to the local access point:

private boolean connectToSSID (String SSID, String passphrase) {

    WifiNetworkSpecifier.Builder builder = new WifiNetworkSpecifier.Builder();
    builder.setSsid(SSID);
    builder.setWpa2Passphrase(passphrase);
    WifiNetworkSpecifier wifiNetworkSpecifier = builder.build();

    NetworkRequest.Builder networkRequestBuilder1 = new NetworkRequest.Builder();
    networkRequestBuilder1.addTransportType(NetworkCapabilities.TRANSPORT_WIFI);
    networkRequestBuilder1.setNetworkSpecifier(wifiNetworkSpecifier);
    NetworkRequest nr = networkRequestBuilder1.build();

    ConnectivityManager cm = (ConnectivityManager)
            context.getSystemService(Context.CONNECTIVITY_SERVICE);

    ConnectivityManager.NetworkCallback networkCallback = new
            ConnectivityManager.NetworkCallback() {
                @Override
                public void onAvailable(Network network) {
                    super.onAvailable(network);
                    cm.bindProcessToNetwork(network);
                    connected = true;
                }
            };
        cm.requestNetwork(nr, networkCallback);

        for (int i = 0; i < 60; i++) {
            SystemClock.sleep(1000);
            if (connected)
                break;
        }
        cm.unregisterNetworkCallback(networkCallback);
        return connected;
}

On successful connection, I send the HTTP request using this code:

try {
        URL url = new URL(str);
        urlConnection = (HttpURLConnection) url.openConnection();
        InputStream in = new BufferedInputStream(urlConnection.getInputStream());
        BufferedReader br = new BufferedReader(new InputStreamReader(in, "UTF-8"));
            String line;
            while ((line = br.readLine()) != null) {
                Log.d (TAG, line);
            }
        Log.d (TAG, "Done");
    } catch (MalformedURLException e) {
        throw new RuntimeException(e);
    } catch (IOException e) {
        Log.d (TAG, "IO exception");
        Log.d (TAG, e.getLocalizedMessage());
    } finally {
        if (urlConnection != null)
            urlConnection.disconnect();
    }

I wondered whether it might be a capabilities issue, for example a NET_CAPABILITY_INTERNET would be a problem, so I checked the capabilities that the network request builder adds automatically and found 13, 14 and 15 (NET_CAPABILITY_NOT_RESTRICTED, NET_CAPABILITY_NOT_VPN and NET_CAPABILITY_TRUSTED). None of these should be a problem.

Do I need to do something to check that the network is ready before I use it? If so, how? If not, I am looking for suggestions for things that might give the ENONET error.