thread_ts=None

app.py

@@ -65,7 +65,7 @@ def monitor_new_posts():
             response = slack_client.chat_postMessage(
                 channel=SLACK_CHANNEL_ID_TEST,
                 text=submission.selftext,
-                thread_ts=thread_ts,
+                thread_ts=None,
                 unfurl_links=False,
                 unfurl_media=False  
             )