diff --git a/lib/session.js b/lib/session.js
index d36fe56d..c10a3ab4 100644
--- a/lib/session.js
+++ b/lib/session.js
@@ -83,7 +83,9 @@ class Session extends Map {
   }
 
   _restore(newConnection, receivedCount) {
-    this.connection.close();
+    if (this.connection) {
+      this.connection.close();
+    }
     this.connection = newConnection;
     for (let i = this.guaranteedDeliveredCount + 1; i <= receivedCount; i++) {
       this.buffer.delete(i);