diff --git a/app/src/main/java/at/bitfire/davdroid/ui/AccountSettingsActivity.java b/app/src/main/java/at/bitfire/davdroid/ui/AccountSettingsActivity.java
index 4c9f589d..de6f973f 100644
--- a/app/src/main/java/at/bitfire/davdroid/ui/AccountSettingsActivity.java
+++ b/app/src/main/java/at/bitfire/davdroid/ui/AccountSettingsActivity.java
@@ -29,6 +29,9 @@ import at.bitfire.davdroid.AccountSettings;
 import at.bitfire.davdroid.App;
 import at.bitfire.davdroid.InvalidAccountException;
 import at.bitfire.davdroid.R;
+import at.bitfire.davdroid.ui.setup.DetectConfigurationFragment;
+import at.bitfire.davdroid.ui.setup.LoginCredentials;
+import at.bitfire.davdroid.ui.setup.LoginCredentialsChangeFragment;
 import at.bitfire.ical4android.TaskProvider;
 
 public class AccountSettingsActivity extends AppCompatActivity {
@@ -95,7 +98,8 @@ public class AccountSettingsActivity extends AppCompatActivity {
             prefPassword.setOnPreferenceChangeListener(new Preference.OnPreferenceChangeListener() {
                 @Override
                 public boolean onPreferenceChange(Preference preference, Object newValue) {
-                    settings.setAuthToken((String)newValue);
+                    LoginCredentials credentials = newValue != null ? new LoginCredentials(account.name, (String) newValue) : null;
+                    LoginCredentialsChangeFragment.newInstance(account, credentials).show(getFragmentManager(), null);
                     refresh();
                     return false;
                 }
diff --git a/app/src/main/java/at/bitfire/davdroid/ui/setup/LoginCredentialsChangeFragment.java b/app/src/main/java/at/bitfire/davdroid/ui/setup/LoginCredentialsChangeFragment.java
new file mode 100644
index 00000000..c0f16be6
--- /dev/null
+++ b/app/src/main/java/at/bitfire/davdroid/ui/setup/LoginCredentialsChangeFragment.java
@@ -0,0 +1,160 @@
+/*
+ * Copyright © 2013 – 2016 Ricki Hirner (bitfire web engineering).
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the GNU Public License v3.0
+ * which accompanies this distribution, and is available at
+ * http://www.gnu.org/licenses/gpl.html
+ */
+
+package at.bitfire.davdroid.ui.setup;
+
+import android.accounts.Account;
+import android.app.Dialog;
+import android.app.ProgressDialog;
+import android.content.Context;
+import android.content.DialogInterface;
+import android.content.Intent;
+import android.os.Bundle;
+import android.support.annotation.NonNull;
+import android.support.v4.app.DialogFragment;
+import android.support.v4.app.LoaderManager;
+import android.support.v4.content.AsyncTaskLoader;
+import android.support.v4.content.Loader;
+import android.support.v7.app.AlertDialog;
+
+import java.util.logging.Level;
+
+import at.bitfire.davdroid.AccountSettings;
+import at.bitfire.davdroid.App;
+import at.bitfire.davdroid.InvalidAccountException;
+import at.bitfire.davdroid.R;
+import at.bitfire.davdroid.ui.DebugInfoActivity;
+import at.bitfire.davdroid.ui.setup.BaseConfigurationFinder.Configuration;
+
+public class LoginCredentialsChangeFragment extends DialogFragment implements LoaderManager.LoaderCallbacks<Configuration> {
+    protected static final String ARG_LOGIN_CREDENTIALS = "credentials",
+            ARG_ACCOUNT = "account";
+    private Account account;
+
+    public static LoginCredentialsChangeFragment newInstance(Account account, LoginCredentials credentials) {
+        LoginCredentialsChangeFragment frag = new LoginCredentialsChangeFragment();
+        Bundle args = new Bundle(1);
+        args.putParcelable(ARG_ACCOUNT, account);
+        args.putParcelable(ARG_LOGIN_CREDENTIALS, credentials);
+        frag.setArguments(args);
+        return frag;
+    }
+
+    @NonNull
+    @Override
+    public Dialog onCreateDialog(Bundle savedInstanceState) {
+        ProgressDialog progress = new ProgressDialog(getActivity());
+        progress.setTitle(R.string.login_configuration_detection);
+        progress.setMessage(getString(R.string.login_querying_server));
+        progress.setIndeterminate(true);
+        progress.setCanceledOnTouchOutside(false);
+        setCancelable(false);
+        return progress;
+    }
+
+    @Override
+    public void onCreate(Bundle savedInstanceState) {
+        super.onCreate(savedInstanceState);
+
+        getLoaderManager().initLoader(0, getArguments(), this);
+        account = getArguments().getParcelable(ARG_ACCOUNT);
+    }
+
+    @Override
+    public Loader<Configuration> onCreateLoader(int id, Bundle args) {
+        return new ServerConfigurationLoader(getContext(), (LoginCredentials) args.getParcelable(ARG_LOGIN_CREDENTIALS));
+    }
+
+    @Override
+    public void onLoadFinished(Loader<Configuration> loader, Configuration data) {
+        if (data != null) {
+            if (data.isFailed())
+                // no service found: show error message
+                getFragmentManager().beginTransaction()
+                        .add(NothingDetectedFragment.newInstance(data.logs), null)
+                        .commitAllowingStateLoss();
+            else {
+                final AccountSettings settings;
+
+                try {
+                    settings = new AccountSettings(getActivity(), account);
+                } catch (InvalidAccountException e) {
+                    App.log.log(Level.INFO, "Account is invalid or doesn't exist (anymore)", e);
+                    getActivity().finish();
+                    return;
+                }
+                settings.setAuthToken(data.authtoken);
+            }
+        } else
+            App.log.severe("Configuration detection failed");
+
+        dismissAllowingStateLoss();
+    }
+
+    @Override
+    public void onLoaderReset(Loader<Configuration> loader) {
+    }
+
+
+    public static class NothingDetectedFragment extends DialogFragment {
+        private static String KEY_LOGS = "logs";
+
+        public static NothingDetectedFragment newInstance(String logs) {
+            Bundle args = new Bundle();
+            args.putString(KEY_LOGS, logs);
+            NothingDetectedFragment fragment = new NothingDetectedFragment();
+            fragment.setArguments(args);
+            return fragment;
+        }
+
+        @Override
+        @NonNull
+        public Dialog onCreateDialog(Bundle savedInstanceState) {
+            return new AlertDialog.Builder(getActivity())
+                    .setTitle(R.string.login_configuration_detection)
+                    .setIcon(R.drawable.ic_error_dark)
+                    .setMessage(R.string.login_no_caldav_carddav)
+                    .setNeutralButton(R.string.login_view_logs, new DialogInterface.OnClickListener() {
+                        @Override
+                        public void onClick(DialogInterface dialog, int which) {
+                            Intent intent = new Intent(getActivity(), DebugInfoActivity.class);
+                            intent.putExtra(DebugInfoActivity.KEY_LOGS, getArguments().getString(KEY_LOGS));
+                            startActivity(intent);
+                        }
+                    })
+                    .setPositiveButton(android.R.string.ok, new DialogInterface.OnClickListener() {
+                        @Override
+                        public void onClick(DialogInterface dialog, int which) {
+                            // dismiss
+                        }
+                    })
+                    .create();
+        }
+    }
+
+    static class ServerConfigurationLoader extends AsyncTaskLoader<Configuration> {
+        final Context context;
+        final LoginCredentials credentials;
+
+        public ServerConfigurationLoader(Context context, LoginCredentials credentials) {
+            super(context);
+            this.context = context;
+            this.credentials = credentials;
+        }
+
+        @Override
+        protected void onStartLoading() {
+            forceLoad();
+        }
+
+        @Override
+        public Configuration loadInBackground() {
+            return new BaseConfigurationFinder(context, credentials).findInitialConfiguration();
+        }
+    }
+}