diff --git a/src/App/src/pages/PlanPage.tsx b/src/App/src/pages/PlanPage.tsx
index 981323e9a..fe9799e71 100644
--- a/src/App/src/pages/PlanPage.tsx
+++ b/src/App/src/pages/PlanPage.tsx
@@ -182,19 +182,37 @@ const PlanPage: React.FC = () => {
         if (!planApprovalRequest) return;
         dispatch(setProcessingApproval(true));
         const id = showToast('Submitting Approval', 'progress');
-        try {
-            await apiService.approvePlan({
+
+        const submitApproval = () =>
+            apiService.approvePlan({
                 m_plan_id: planApprovalRequest.id,
                 plan_id: planData?.plan?.id ?? '',
                 approved: true,
                 feedback: 'Plan approved by user',
             });
+
+        try {
+            await submitApproval();
             dismissToast(id);
             /* P0: single compound action replaces 3 separate dispatches */
             dispatch(planApprovalAccepted());
-        } catch {
-            dismissToast(id);
-            showToast('Failed to submit approval', 'error');
+        } catch (firstError) {
+            // Approval failed — the backend may have timed out or the WS dropped.
+            // Reconnect the WebSocket and retry once before giving up.
+            try {
+                if (!webSocketService.isConnected() && planData?.plan?.id) {
+                    await webSocketService.connect(planData.plan.id);
+                }
+                await submitApproval();
+                dismissToast(id);
+                dispatch(planApprovalAccepted());
+            } catch {
+                dismissToast(id);
+                showToast(
+                    'Failed to submit approval. The plan may have timed out — please start a new task and try again.',
+                    'error',
+                );
+            }
         } finally {
             dispatch(setProcessingApproval(false));
         }
diff --git a/src/App/src/store/WebSocketService.tsx b/src/App/src/store/WebSocketService.tsx
index 7fff80a56..9c532b208 100644
--- a/src/App/src/store/WebSocketService.tsx
+++ b/src/App/src/store/WebSocketService.tsx
@@ -11,6 +11,7 @@ class WebSocketService {
     private listeners: Map<string, Set<(message: StreamMessage) => void>> = new Map();
     private planSubscriptions: Set<string> = new Set();
     private reconnectTimer: ReturnType<typeof setTimeout> | null = null;
+    private keepaliveTimer: ReturnType<typeof setInterval> | null = null;
     private isConnecting = false;
     private intentionalDisconnect = false;
     private lastPlanId: string | undefined;
@@ -59,6 +60,7 @@ class WebSocketService {
                         clearTimeout(this.reconnectTimer);
                         this.reconnectTimer = null;
                     }
+                    this.startKeepalive();
                     this.emit('connection_status', { connected: true });
                     resolve();
                 };
@@ -75,6 +77,7 @@ class WebSocketService {
                 this.ws.onclose = (event) => {
                     this.isConnecting = false;
                     this.ws = null;
+                    this.stopKeepalive();
                     this.emit('connection_status', { connected: false });
                     /* P1: Only auto-reconnect if not intentional and not a clean close */
                     if (!this.intentionalDisconnect && event.code !== 1000 &&
@@ -99,6 +102,7 @@ class WebSocketService {
 
     disconnect(): void {
         this.intentionalDisconnect = true;
+        this.stopKeepalive();
         if (this.reconnectTimer) {
             clearTimeout(this.reconnectTimer);
             this.reconnectTimer = null;
@@ -197,6 +201,11 @@ class WebSocketService {
     }
 
     private handleMessage(message: StreamMessage): void {
+        // Ignore keepalive ping/pong messages from the server
+        const msgType = message.type as string;
+        if (msgType === 'ping' || msgType === 'pong') {
+            return;
+        }
 
         switch (message.type) {
             case WebsocketMessageType.PLAN_APPROVAL_REQUEST: {
@@ -277,6 +286,28 @@ class WebSocketService {
         }
     }
 
+    private startKeepalive(): void {
+        this.stopKeepalive();
+        // Send a ping every 30 seconds to prevent idle timeout from
+        // Azure Container Apps / reverse proxies closing the WebSocket.
+        this.keepaliveTimer = setInterval(() => {
+            if (this.ws && this.ws.readyState === WebSocket.OPEN) {
+                try {
+                    this.ws.send(JSON.stringify({ type: 'pong' }));
+                } catch {
+                    // If send fails, the onclose handler will trigger reconnect
+                }
+            }
+        }, 30_000);
+    }
+
+    private stopKeepalive(): void {
+        if (this.keepaliveTimer) {
+            clearInterval(this.keepaliveTimer);
+            this.keepaliveTimer = null;
+        }
+    }
+
     private attemptReconnect(): void {
         if (this.reconnectAttempts >= this.maxReconnectAttempts) {
             this.emit('error', { error: 'Max reconnection attempts reached' });
diff --git a/src/backend/v4/api/router.py b/src/backend/v4/api/router.py
index 2a3d5fd97..6c92776e3 100644
--- a/src/backend/v4/api/router.py
+++ b/src/backend/v4/api/router.py
@@ -93,18 +93,23 @@ async def start_comms(
         # Keep the connection open - FastAPI will close the connection if this returns
         try:
             # Keep the connection open - FastAPI will close the connection if this returns
+            # Send periodic pings to prevent idle timeout from Azure infra / reverse proxies.
+            ping_interval = 30  # seconds
             while True:
                 # no expectation that we will receive anything from the client but this keeps
                 # the connection open and does not take cpu cycle
                 try:
-                    message = await websocket.receive_text()
+                    message = await asyncio.wait_for(
+                        websocket.receive_text(), timeout=ping_interval
+                    )
                     logging.debug(f"Received WebSocket message from {user_id}: {message}")
                 except asyncio.TimeoutError:
-                    # Ignore timeouts to keep the WebSocket connection open, but avoid a tight loop.
-                    logging.debug(
-                        f"WebSocket receive timeout for user {user_id}, process {process_id}"
-                    )
-                    await asyncio.sleep(0.1)
+                    # No message received within ping_interval — send a ping to keep alive.
+                    try:
+                        await websocket.send_text('{"type":"ping"}')
+                    except Exception:
+                        logging.info(f"Ping failed for {user_id}/{process_id}, connection likely closed")
+                        break
                 except WebSocketDisconnect:
                     dc_props = {"process_id": process_id, "user_id": user_id}
                     if session_id:
@@ -537,7 +542,8 @@ async def plan_approval(
                     human_feedback.m_plan_id
                 )
                 raise HTTPException(
-                    status_code=404, detail="No active plan found for approval"
+                    status_code=404,
+                    detail="No active plan found for approval. The plan may have timed out due to inactivity. Please start a new task.",
                 )
     except Exception as e:
         logging.error(f"Error processing plan approval: {e}")
diff --git a/src/backend/v4/config/settings.py b/src/backend/v4/config/settings.py
index fa112fcd9..9c88488a8 100644
--- a/src/backend/v4/config/settings.py
+++ b/src/backend/v4/config/settings.py
@@ -97,8 +97,8 @@ def __init__(self):
         self._approval_events: Dict[str, asyncio.Event] = {}
         self._clarification_events: Dict[str, asyncio.Event] = {}
 
-        # Default timeout (seconds) for waiting operations
-        self.default_timeout: float = 300.0
+        # Default timeout (seconds) for waiting operations.
+        self.default_timeout: float = 1800.0
 
     def get_current_orchestration(self, user_id: str) -> Any:
         """Get existing orchestration workflow instance for user_id."""
diff --git a/src/tests/backend/v4/config/test_settings.py b/src/tests/backend/v4/config/test_settings.py
index 1c055fe33..3d894c0ae 100644
--- a/src/tests/backend/v4/config/test_settings.py
+++ b/src/tests/backend/v4/config/test_settings.py
@@ -212,7 +212,7 @@ def test_orchestration_config_creation(self):
         self.assertEqual(config.max_rounds, 20)
         self.assertIsInstance(config._approval_events, dict)
         self.assertIsInstance(config._clarification_events, dict)
-        self.assertEqual(config.default_timeout, 300.0)
+        self.assertEqual(config.default_timeout, 1800.0)
 
     def test_get_current_orchestration(self):
         """Test getting current orchestration."""