diff --git a/src/web/auto-reply.web-auto-reply.reconnects-after-connection-close.test.ts b/src/web/auto-reply.web-auto-reply.reconnects-after-connection-close.test.ts
index f6eca287621..678cf0d37c6 100644
--- a/src/web/auto-reply.web-auto-reply.reconnects-after-connection-close.test.ts
+++ b/src/web/auto-reply.web-auto-reply.reconnects-after-connection-close.test.ts
@@ -145,6 +145,56 @@ describe("web auto-reply", () => {
       expect(runtime.error).toHaveBeenCalledWith(expect.stringContaining(scenario.expectedError));
     }
   });
+
+  it("treats status 440 as non-retryable and stops without retrying", async () => {
+    const closeResolvers: Array<(reason?: unknown) => void> = [];
+    const sleep = vi.fn(async () => {});
+    const listenerFactory = vi.fn(async () => {
+      const onClose = new Promise<unknown>((res) => {
+        closeResolvers.push(res);
+      });
+      return { close: vi.fn(), onClose };
+    });
+    const { runtime, controller, run } = startMonitorWebChannel({
+      monitorWebChannelFn: monitorWebChannel as never,
+      listenerFactory,
+      sleep,
+      reconnect: { initialMs: 10, maxMs: 10, maxAttempts: 3, factor: 1.1 },
+    });
+
+    await Promise.resolve();
+    expect(listenerFactory).toHaveBeenCalledTimes(1);
+    closeResolvers.shift()?.({
+      status: 440,
+      isLoggedOut: false,
+      error: "Unknown Stream Errored (conflict)",
+    });
+
+    const completedQuickly = await Promise.race([
+      run.then(() => true),
+      new Promise<boolean>((resolve) => setTimeout(() => resolve(false), 60)),
+    ]);
+
+    if (!completedQuickly) {
+      await vi.waitFor(
+        () => {
+          expect(listenerFactory).toHaveBeenCalledTimes(2);
+        },
+        { timeout: 250, interval: 2 },
+      );
+      controller.abort();
+      closeResolvers[1]?.({ status: 499, isLoggedOut: false, error: "aborted" });
+      await run;
+    }
+
+    expect(completedQuickly).toBe(true);
+    expect(listenerFactory).toHaveBeenCalledTimes(1);
+    expect(sleep).not.toHaveBeenCalled();
+    expect(runtime.error).toHaveBeenCalledWith(expect.stringContaining("status 440"));
+    expect(runtime.error).toHaveBeenCalledWith(expect.stringContaining("session conflict"));
+    expect(runtime.error).toHaveBeenCalledWith(expect.stringContaining("Stopping web monitoring"));
+  });
+
   it("forces reconnect when watchdog closes without onClose", async () => {
     vi.useFakeTimers();
     try {
diff --git a/src/web/auto-reply/monitor.ts b/src/web/auto-reply/monitor.ts
index cab3490fedd..b7e2bb2683f 100644
--- a/src/web/auto-reply/monitor.ts
+++ b/src/web/auto-reply/monitor.ts
@@ -31,6 +31,12 @@ import { createWebOnMessageHandler } from "./monitor/on-message.js";
 import type { WebChannelStatus, WebInboundMsg, WebMonitorTuning } from "./types.js";
 import { isLikelyWhatsAppCryptoError } from "./util.js";
 
+function isNonRetryableWebCloseStatus(statusCode: unknown): boolean {
+  // WhatsApp 440 = session conflict ("Unknown Stream Errored (conflict)").
+  // This is persistent until the operator resolves the conflicting session.
+  return statusCode === 440;
+}
+
 export async function monitorWebChannel(
   verbose: boolean,
   listenerFactory: typeof monitorWebInbox | undefined = monitorWebInbox,
@@ -402,6 +408,22 @@ export async function monitorWebChannel(
       break;
     }
 
+    if (isNonRetryableWebCloseStatus(statusCode)) {
+      reconnectLogger.warn(
+        {
+          connectionId,
+          status: statusCode,
+          error: errorStr,
+        },
+        "web reconnect: non-retryable close status; stopping monitor",
+      );
+      runtime.error(
+        `WhatsApp Web connection closed (status ${statusCode}: session conflict). Resolve conflicting WhatsApp Web sessions, then relink with \`${formatCliCommand("openclaw channels login --channel web")}\`. Stopping web monitoring.`,
+      );
+      await closeListener();
+      break;
+    }
+
     reconnectAttempts += 1;
     status.reconnectAttempts = reconnectAttempts;
     emitStatus();