diff --git a/changedetectionio/notification/apprise_plugin/browser_notification_helpers.py b/changedetectionio/notification/apprise_plugin/browser_notification_helpers.py
index d21b8507e..2ff7da057 100644
--- a/changedetectionio/notification/apprise_plugin/browser_notification_helpers.py
+++ b/changedetectionio/notification/apprise_plugin/browser_notification_helpers.py
@@ -11,32 +11,44 @@ from loguru import logger
 
 def convert_pem_private_key_for_pywebpush(private_key):
     """
-    Convert PEM private key to the raw bytes format that pywebpush expects
+    Convert PEM private key to the format that pywebpush expects
     
     Args:
         private_key: PEM private key string or already converted key
         
     Returns:
-        Private key in the format pywebpush expects
+        Private key in the format pywebpush expects (PEM string for pywebpush)
     """
-    if not isinstance(private_key, str) or not private_key.startswith('-----BEGIN'):
+    # pywebpush expects the PEM string directly
+    if not isinstance(private_key, str):
+        return private_key
+        
+    # If it doesn't look like PEM, return as-is
+    if not private_key.startswith('-----BEGIN'):
         return private_key
         
     try:
         from cryptography.hazmat.primitives import serialization
-        private_key_bytes = private_key.encode()
+        from cryptography.hazmat.primitives.asymmetric import ec
+        
+        # Validate the key by loading it
+        private_key_bytes = private_key.encode('utf-8')
         private_key_obj = serialization.load_pem_private_key(private_key_bytes, password=None)
         
-        # Get raw private key bytes for pywebpush
-        private_key_raw = private_key_obj.private_bytes(
-            encoding=serialization.Encoding.Raw,
-            format=serialization.PrivateFormat.Raw,
-            encryption_algorithm=serialization.NoEncryption()
-        )
-        return private_key_raw
+        # Verify it's an ECDSA key (required for VAPID)
+        if not isinstance(private_key_obj, ec.EllipticCurvePrivateKey):
+            logger.error("Private key is not an ECDSA key - VAPID requires ECDSA")
+            return private_key
+            
+        # Ensure the key has the right curve (P-256 for VAPID)
+        if private_key_obj.curve.name != 'secp256r1':
+            logger.warning(f"Private key uses curve {private_key_obj.curve.name}, VAPID recommends secp256r1 (P-256)")
+            
+        # Return the original PEM - pywebpush handles PEM format correctly
+        return private_key
         
     except Exception as e:
-        logger.warning(f"Failed to convert private key format, using as-is: {e}")
+        logger.warning(f"Failed to validate private key format: {e}")
         return private_key
 
 
diff --git a/changedetectionio/static/js/browser-notifications.js b/changedetectionio/static/js/browser-notifications.js
index d34e55861..f0101bfbe 100644
--- a/changedetectionio/static/js/browser-notifications.js
+++ b/changedetectionio/static/js/browser-notifications.js
@@ -159,6 +159,9 @@ class BrowserNotifications {
                 return;
             }
 
+            // First, try to clear any existing subscription with different keys
+            await this.clearExistingSubscription();
+
             // Create push subscription
             const subscription = await this.serviceWorkerRegistration.pushManager.subscribe({
                 userVisibleOnly: true,
@@ -196,7 +199,13 @@ class BrowserNotifications {
 
         } catch (error) {
             console.error(`Failed to subscribe to keyword ${keyword}:`, error);
-            alert(`Failed to subscribe: ${error.message}`);
+            
+            // Show user-friendly error message
+            if (error.message.includes('different applicationServerKey')) {
+                this.showSubscriptionConflictDialog(keyword, error);
+            } else {
+                alert(`Failed to subscribe: ${error.message}`);
+            }
         }
     }
 
@@ -319,6 +328,74 @@ class BrowserNotifications {
         return outputArray;
     }
 
+    async clearExistingSubscription() {
+        /**
+         * Clear any existing push subscription that might conflict with our VAPID keys
+         */
+        try {
+            const existingSubscription = await this.serviceWorkerRegistration.pushManager.getSubscription();
+            
+            if (existingSubscription) {
+                console.log('Found existing subscription, unsubscribing...');
+                await existingSubscription.unsubscribe();
+                console.log('Successfully cleared existing subscription');
+            }
+        } catch (error) {
+            console.warn('Failed to clear existing subscription:', error);
+            // Don't throw - this is just cleanup
+        }
+    }
+
+    showSubscriptionConflictDialog(keyword, error) {
+        /**
+         * Show user-friendly dialog for subscription conflicts
+         */
+        const message = `Browser notifications are already set up for a different changedetection.io instance or with different settings.
+
+To fix this:
+1. Clear your existing subscription 
+2. Try subscribing again
+
+Would you like to automatically clear the old subscription and retry?`;
+
+        if (confirm(message)) {
+            this.clearExistingSubscription().then(() => {
+                // Retry subscription after clearing
+                setTimeout(() => {
+                    this.subscribeToKeyword(keyword);
+                }, 500);
+            });
+        } else {
+            alert('To use browser notifications, please manually clear your browser notifications for this site in browser settings, then try again.');
+        }
+    }
+
+    async clearAllNotifications() {
+        /**
+         * Clear all browser notification subscriptions (admin function)
+         */
+        try {
+            // Clear service worker subscription
+            const existingSubscription = await this.serviceWorkerRegistration.pushManager.getSubscription();
+            if (existingSubscription) {
+                await existingSubscription.unsubscribe();
+            }
+
+            // Clear local storage
+            this.subscriptions.clear();
+            
+            // Update UI
+            this.updateSubscriptionsList();
+            
+            console.log('All notifications cleared');
+            alert('All browser notifications have been cleared. You can now subscribe again.');
+            
+        } catch (error) {
+            console.error('Failed to clear all notifications:', error);
+            alert('Failed to clear notifications. Please manually clear them in browser settings.');
+        }
+    }
+
     async handleAutoSubscription() {
         // Handle auto-subscription for keywords detected from browser:// URLs
         try {
diff --git a/changedetectionio/templates/_common_fields.html b/changedetectionio/templates/_common_fields.html
index 1ae41c52c..2795fc142 100644
--- a/changedetectionio/templates/_common_fields.html
+++ b/changedetectionio/templates/_common_fields.html
@@ -41,6 +41,7 @@
                             <div class="pure-form-message-inline">
                                 <p><strong>Browser Notification Channels</strong> - These are automatically detected when you use <code>browser://keyword</code> URLs in your notification settings above.</p>
                                 <p>When detected, you'll be prompted to enable browser notifications for these channels so you can receive real-time push notifications even when this tab is closed.</p>
+                                <p><small><strong>Troubleshooting:</strong> If you get "different applicationServerKey" errors, click "Clear All Notifications" below and try again. This happens when switching between different changedetection.io instances.</small></p>
                                 <div id="browser-notification-controls" style="margin-top: 1em;">
                                     <div id="notification-permission-status">
                                         <p>Browser notifications: <span id="permission-status">checking...</span></p>
@@ -52,6 +53,9 @@
                                         <button type="button" id="test-notification-btn" class="pure-button button-secondary button-xsmall" style="display: none;">
                                             Test Notification
                                         </button>
+                                        <button type="button" id="clear-notifications-btn" class="pure-button button-secondary button-xsmall" onclick="window.browserNotifications?.clearAllNotifications()" style="margin-left: 0.5em;">
+                                            Clear All Notifications
+                                        </button>
                                     </div>
                                 </div>
                             </div>