diff --git a/lib/imap-notifier.js b/lib/imap-notifier.js
index 82e36a00..86fe462c 100644
--- a/lib/imap-notifier.js
+++ b/lib/imap-notifier.js
@@ -393,7 +393,7 @@ class ImapNotifier extends EventEmitter {
         }
 
         let rlkey = 'lim:' + data.service;
-        const { closed: socketClosed, connecting, destroyed } = data.session.socket;
+        const { closed: socketClosed, connecting, destroyed } = data.session?.socket || {};
 
         if (!socketClosed && !connecting && !destroyed) {
             // socket alive, not closed
@@ -411,7 +411,7 @@ class ImapNotifier extends EventEmitter {
                 return callback(null, true);
             });
         } else {
-            // socket dead/closed
+            // socket dead/closed/undefined
             const err = new Error('[ALERT] Socket closed unexpectedly before authentication completed.');
             err.response = 'NO';
             return callback(err, false);