diff --git a/backend/routes/mikrotikConfigRoutes.js b/backend/routes/mikrotikConfigRoutes.js
index 6bbb5eb..0fc5964 100644
--- a/backend/routes/mikrotikConfigRoutes.js
+++ b/backend/routes/mikrotikConfigRoutes.js
@@ -241,6 +241,14 @@ async function applyMikrotikConfig(req, res) {
   const mikrotikRequests = [];
   const body = req.body || {};
   console.log('[MikroTik apply] Request body:', { serverId: body.serverId, type: body.type, dryRun: body.dryRun });
+  const sendSafe = (status, data) => {
+    if (res.headersSent) return;
+    try {
+      res.status(status).json(data);
+    } catch (e) {
+      console.error('[MikroTik apply] sendSafe failed:', e);
+    }
+  };
   try {
     const { serverId, type = 'all', dryRun = true } = body;
     if (!serverId) {
@@ -344,7 +352,7 @@ async function applyMikrotikConfig(req, res) {
           msg.includes('Authentication') || msg.includes('login') ? 'Неверный логин или пароль' : msg,
     };
     if (mikrotikRequests.length > 0) errPayload.mikrotikRequests = mikrotikRequests;
-    return res.status(500).json(errPayload);
+    sendSafe(500, errPayload);
   }
 }
 
diff --git a/backend/server.js b/backend/server.js
index 06473f7..e0dca61 100644
--- a/backend/server.js
+++ b/backend/server.js
@@ -450,6 +450,7 @@ app.post('/api/mikrotik/generate', mikrotikConfigRoutes.generateMikrotikConfig);
 app.get('/api/mikrotik/generate-interfaces', mikrotikConfigRoutes.generateInterfaces);
 app.get('/api/mikrotik/generate-recursive-routes', mikrotikConfigRoutes.generateRecursiveRoutes);
 app.post('/api/mikrotik/test-connection', mikrotikConfigRoutes.testMikrotikConnection);
+app.get('/api/mikrotik/ping', (req, res) => res.json({ ok: true, ts: Date.now() }));
 app.post('/api/mikrotik/apply', mikrotikConfigRoutes.applyMikrotikConfig);
 
 // === MIKROTIK VALIDATION ===
diff --git a/frontend/src/NetworkConfigManager.jsx b/frontend/src/NetworkConfigManager.jsx
index ffebbce..86847c3 100644
--- a/frontend/src/NetworkConfigManager.jsx
+++ b/frontend/src/NetworkConfigManager.jsx
@@ -2279,11 +2279,18 @@ function NetworkConfigManager() {
     }
   };
 
-  const openApplyModal = (serverId) => {
+  const openApplyModal = async (serverId) => {
     setApplyServerId(serverId);
     setApplyResult(null);
     setApplyDryRun(true);
     setApplyModalOpen(true);
+    try {
+      const r = await fetch('/api/mikrotik/ping');
+      const d = await r.json().catch(() => ({}));
+      console.log('[MikroTik apply] Backend ping:', r.ok ? 'OK' : 'FAIL', d);
+    } catch (e) {
+      console.warn('[MikroTik apply] Backend ping failed:', e.message);
+    }
   };
 
   // === Генерация кода MikroTik только для одного интерфейса ===