diff --git a/apps/chat.js b/apps/chat.js
index 85d227a..de3d25c 100644
--- a/apps/chat.js
+++ b/apps/chat.js
@@ -695,7 +695,7 @@ export class chatgpt extends plugin {
         }
       }
       let ctime = new Date()
-      previousConversation = await redis.get(key) || JSON.stringify({
+      previousConversation = (key ? await redis.get(key) : null) || JSON.stringify({
         sender: e.sender,
         ctime,
         utime: ctime,