diff --git a/app.py b/app.py
index 3a648ce..a080753 100644
--- a/app.py
+++ b/app.py
@@ -1422,10 +1422,14 @@ async def _xui_fetch_clients(client: httpx.AsyncClient, base_url: str, headers:
     return []
 
 
-async def sync_users_with_xui(data: dict):
-    """Import / update panel users from an existing 3x-ui instance."""
+async def sync_users_with_xui(data: dict, *, force: bool = False):
+    """Import / update panel users from an existing 3x-ui instance.
+
+    force=True: used by the manual "Sync now" button (ignores xui_sync_users flag).
+    Background jobs keep force=False and only run when xui_sync_users is enabled.
+    """
     settings = data.get('settings', {}).get('sync', {})
-    if not settings.get('xui_sync_users'):
+    if not force and not settings.get('xui_sync_users'):
         return 0, "3x-ui synchronization is disabled in settings"
 
     url = (settings.get('xui_url') or '').strip()
@@ -4042,8 +4046,34 @@ async def api_xui_sync_now(request: Request):
     if not _check_admin(request):
         return JSONResponse({'error': 'Forbidden'}, status_code=403)
     data = load_data()
-    count, msg = await sync_users_with_xui(data)
-    return {'status': 'success', 'count': count, 'message': msg}
+
+    # Allow syncing with credentials from the request body (form may not be saved yet)
+    try:
+        body = await request.json()
+    except Exception:
+        body = {}
+    if isinstance(body, dict) and body:
+        sync_cfg = data.setdefault('settings', {}).setdefault('sync', {})
+        for key in (
+            'xui_url', 'xui_username', 'xui_password', 'xui_api_token',
+            'xui_create_conns', 'xui_server_id', 'xui_protocol', 'xui_sync_users', 'xui_sync',
+        ):
+            if key in body and body[key] is not None:
+                sync_cfg[key] = body[key]
+        # Persist so background sync / next page load keep the values
+        async with DATA_LOCK:
+            current = load_data()
+            current.setdefault('settings', {}).setdefault('sync', {}).update(sync_cfg)
+            save_data(current)
+        data = current
+
+    count, msg = await sync_users_with_xui(data, force=True)
+    ok = count > 0 or (isinstance(msg, str) and msg.startswith('Successfully'))
+    return {
+        'status': 'success' if ok else 'error',
+        'count': count,
+        'message': msg,
+    }
 
 
 @app.post('/api/settings/xui_sync_delete', tags=["Settings"])
diff --git a/templates/settings.html b/templates/settings.html
index 597267f..cb6fe73 100644
--- a/templates/settings.html
+++ b/templates/settings.html
@@ -881,23 +881,35 @@
         const btn = document.getElementById('xuiSyncNowBtn');
         const text = document.getElementById('xuiSyncNowBtnText');
         const spinner = document.getElementById('xuiSyncNowSpinner');
+        const syncForm = document.getElementById('syncForm');
 
         btn.disabled = true;
         text.textContent = _('sync_running');
         spinner.classList.remove('hidden');
 
         try {
-            const res = await fetch('/api/settings/xui_sync_now', { method: 'POST' });
+            const payload = {
+                xui_sync: true,
+                xui_sync_users: true,
+                xui_url: syncForm.xui_url.value.trim(),
+                xui_username: syncForm.xui_username.value.trim(),
+                xui_password: syncForm.xui_password.value,
+                xui_api_token: syncForm.xui_api_token.value.trim(),
+                xui_create_conns: syncForm.xui_create_conns.checked,
+                xui_server_id: parseInt(syncForm.xui_server_id.value || '0'),
+                xui_protocol: syncForm.xui_protocol.value
+            };
+            const res = await fetch('/api/settings/xui_sync_now', {
+                method: 'POST',
+                headers: { 'Content-Type': 'application/json' },
+                body: JSON.stringify(payload)
+            });
             const data = await res.json();
             if (data.status === 'success') {
                 showToast(_('sync_success').replace('{}', data.count), 'success');
-                if (data.message && data.count === 0) {
-                    showToast(data.message, 'error');
-                } else {
-                    setTimeout(() => window.location.reload(), 1500);
-                }
+                setTimeout(() => window.location.reload(), 1500);
             } else {
-                throw new Error(data.message || 'Error occurred');
+                throw new Error(data.message || data.error || 'Error occurred');
             }
         } catch (err) {
             showToast(`${_('error')}: ` + err.message, 'error');