I have an android app that connects to HelioHost. My app runs fine on the emulator (API 33) but when I run it on a real device (API 22) I get the following exception:

javax.net.ssl.SSLHandshakeException: java.security.cert.CertPathValidatorException: Trust anchor for certification path not found.

Here is the code that produces the exception:

protected String doInBackground(String... strings) {
            String username = strings[0];
            String activationKey = strings[1];
            InputStream inStream = null;
            String response = null;
            
            try {
                ContentValues values=new ContentValues();
                values.put("username", username);
                values.put("activationKey", activationKey);
                URL url = new URL("https://zelda82.heliohost.org/activation.php");
                HttpsURLConnection conn = (HttpsURLConnection) url.openConnection();
                conn.setRequestMethod("POST");
                conn.setDoInput(true);
                conn.setDoOutput(true);

                OutputStream os = conn.getOutputStream();
                BufferedWriter writer = new BufferedWriter(new OutputStreamWriter(os, "UTF-8"));

                writer.write(getQuery(values));
                writer.flush();
                writer.close();
                os.close();

                BufferedReader reader = new BufferedReader(new InputStreamReader((conn.getInputStream())));
                response = reader.readLine();
                reader.close();
            }

            catch(Exception e) {
                e.printStackTrace();
            }

            return response;
        }

I didn’t have this problem before them doing a maintenance. Is it possible that there is a server misconfiguration?