diff --git a/app.py b/app.py
index 436a491..f1cdc58 100644
--- a/app.py
+++ b/app.py
@@ -69,27 +69,29 @@ class FlicButtonHandler:
             raise
 
     def _decode_vapid_private_key(self):
-        """Load and validate VAPID private key with strict formatting."""
+        """Load and strictly validate VAPID private key."""
         try:
+            # Get and clean the key
             env_key = os.getenv('VAPID_PRIVATE_KEY', '').strip().strip('"\'')
-
-            # Convert to consistent PEM format
+            
+            # Convert to clean PEM format
             if '\\n' in env_key:
                 private_pem = env_key.replace('\\n', '\n')
             else:
                 private_pem = env_key
-
+                
             # Ensure proper PEM headers
             if not private_pem.startswith('-----BEGIN PRIVATE KEY-----'):
                 private_pem = f"-----BEGIN PRIVATE KEY-----\n{private_pem}\n-----END PRIVATE KEY-----"
-
-            # Validate by loading
+                
+            # Strict validation
             key = serialization.load_pem_private_key(
                 private_pem.encode('utf-8'),
-                password=None
+                password=None,
+                backend=default_backend()
             )
             
-            # Return standardized PEM
+            # Return in strict PEM format
             return key.private_bytes(
                 encoding=serialization.Encoding.PEM,
                 format=serialization.PrivateFormat.PKCS8,
@@ -97,8 +99,8 @@ class FlicButtonHandler:
             ).decode('utf-8')
             
         except Exception as e:
-            logger.error(f"VAPID key loading failed: {str(e)}")
-            raise ValueError("Invalid VAPID private key format") from e
+            logger.error(f"CRITICAL: Invalid VAPID key - {str(e)}")
+            raise RuntimeError("Invalid VAPID private key configuration") from e
 
     def load_subscriptions(self) -> List[Dict]:
         """Load web push subscriptions from file."""
@@ -120,50 +122,29 @@ class FlicButtonHandler:
             logger.error(f"Error saving subscriptions: {e}")
 
     async def send_push_notification(self, subscription: Dict, message: str):
-        """Send a web push notification with robust key handling."""
         try:
-            if not self.subscriptions:
-                logger.warning("No subscriptions available")
-                return
-
-            # Convert PEM key to bytes right before use
-            try:
-                private_key = serialization.load_pem_private_key(
-                    self.vapid_private_key.encode('utf-8'),
-                    password=None
-                )
-                # Re-serialize to ensure clean format
-                vapid_private_key = private_key.private_bytes(
-                    encoding=serialization.Encoding.PEM,
-                    format=serialization.PrivateFormat.PKCS8,
-                    encryption_algorithm=serialization.NoEncryption()
-                ).decode('utf-8')
-            except Exception as e:
-                logger.error(f"Key conversion failed: {str(e)}")
-                raise
-
-            # Extract domain for aud claim
+            # Get endpoint base for aud claim
             endpoint = subscription['endpoint']
-            aud = endpoint.split('/fcm/send')[0] if 'fcm.googleapis.com' in endpoint else endpoint.split('/send')[0]
+            aud = endpoint.split('/send')[0] if '/send' in endpoint else endpoint.split('/fcm/send')[0]
             
+            logger.debug(f"Sending to: {endpoint[:50]}...")
             logger.debug(f"Using aud: {aud}")
-            logger.debug(f"Key length: {len(vapid_private_key)}")
 
             webpush(
                 subscription_info=subscription,
                 data=message,
-                vapid_private_key=vapid_private_key,
+                vapid_private_key=self.vapid_private_key,
                 vapid_claims={
-                    "sub": os.getenv('VAPID_CLAIM_EMAIL', 'mailto:your-email@example.com'),
-                    "aud": aud
-                }
+                    "sub": os.getenv('VAPID_CLAIM_EMAIL'),
+                    "aud": aud + "/"  # Ensure trailing slash
+                },
+                ttl=86400  # 24 hour expiration
             )
             logger.info("Push notification sent successfully")
-        except WebPushException as e:
+            return True
+        except Exception as e:
             logger.error(f"Push failed: {str(e)}")
-            if 'Invalid JWT' in str(e):
-                logger.error("VAPID key validation failed")
-            raise
+            return False
 
     async def handle_button1(self):
         """Handle first button action - e.g., Home Lights On"""