diff --git a/public/manifest.webmanifest b/public/manifest.webmanifest
index dd061cf..405cfde 100644
--- a/public/manifest.webmanifest
+++ b/public/manifest.webmanifest
@@ -9,6 +9,7 @@
   "orientation": "portrait",
   "background_color": "#000000",
   "theme_color": "#000000",
+  "gcm_sender_id": "103953800507",
   "icons": [
     {
       "src": "/images/app-icon-192.png",
diff --git a/public/sw.js b/public/sw.js
index 339da63..c8bc1e2 100644
--- a/public/sw.js
+++ b/public/sw.js
@@ -1,4 +1,4 @@
-const CACHE_NAME = 'l484-pwa-v3'
+const CACHE_NAME = 'l484-pwa-v4'
 const APP_SHELL = [
   '/',
   '/manifest.webmanifest',
diff --git a/src/services/notifications.js b/src/services/notifications.js
index 5c57c63..2721d1e 100644
--- a/src/services/notifications.js
+++ b/src/services/notifications.js
@@ -19,29 +19,7 @@ export const notificationSupport = () => ({
   secure: window.isSecureContext || window.location.hostname === 'localhost' || window.location.hostname === '127.0.0.1',
 })
 
-export const subscribeToNotifications = async () => {
-  const support = notificationSupport()
-  if (!support.supported) throw new Error('Push notifications are not supported in this browser.')
-  if (!support.secure) throw new Error('Push notifications require HTTPS.')
-
-  const keyResponse = await fetch('/api/notifications/vapid-public-key')
-  const keyData = await keyResponse.json().catch(() => ({}))
-  if (!keyResponse.ok || !keyData.publicKey) throw new Error('VAPID public key is not configured.')
-
-  const requested = await Notification.requestPermission()
-  permission.value = requested
-  if (requested !== 'granted') throw new Error('Notification permission was not granted.')
-
-  const registration = await navigator.serviceWorker.register('/sw.js')
-  await navigator.serviceWorker.ready
-  const existing = await registration.pushManager.getSubscription()
-  if (existing) await existing.unsubscribe()
-
-  const subscription = await registration.pushManager.subscribe({
-    userVisibleOnly: true,
-    applicationServerKey: urlBase64ToUint8Array(keyData.publicKey),
-  })
-
+const saveSubscription = async (subscription) => {
   const response = await fetch('/api/notifications/subscribe', {
     method: 'POST',
     headers: { 'Content-Type': 'application/json' },
@@ -51,3 +29,42 @@ export const subscribeToNotifications = async () => {
   if (!response.ok) throw new Error(data.error || 'Could not save notification subscription.')
   return data
 }
+
+const subscribeWithRetry = async (registration, applicationServerKey) => {
+  try {
+    return await registration.pushManager.subscribe({ userVisibleOnly: true, applicationServerKey })
+  } catch (error) {
+    await registration.update().catch(() => {})
+    await new Promise((resolve) => window.setTimeout(resolve, 350))
+    try {
+      return await registration.pushManager.subscribe({ userVisibleOnly: true, applicationServerKey })
+    } catch {
+      const message = error instanceof Error ? error.message : 'Push service error.'
+      throw new Error(`Push registration failed: ${message}`)
+    }
+  }
+}
+
+export const subscribeToNotifications = async () => {
+  const support = notificationSupport()
+  if (!support.supported) throw new Error('Push notifications are not supported in this browser.')
+  if (!support.secure) throw new Error('Push notifications require HTTPS.')
+
+  const keyResponse = await fetch('/api/notifications/vapid-public-key')
+  const keyData = await keyResponse.json().catch(() => ({}))
+  if (!keyResponse.ok || !keyData.publicKey) throw new Error('VAPID public key is not configured.')
+  if (!keyData.configured) throw new Error('VAPID private key is not configured on the server.')
+  const applicationServerKey = urlBase64ToUint8Array(keyData.publicKey)
+
+  const requested = await Notification.requestPermission()
+  permission.value = requested
+  if (requested !== 'granted') throw new Error('Notification permission was not granted.')
+
+  const registration = await navigator.serviceWorker.register('/sw.js')
+  await navigator.serviceWorker.ready
+  const existing = await registration.pushManager.getSubscription()
+  if (existing) return saveSubscription(existing)
+
+  const subscription = await subscribeWithRetry(registration, applicationServerKey)
+  return saveSubscription(subscription)
+}