Telegram NewMessage Event Handler Not Firing for Large Supergroups (GramJS)

I'm using GramJS (telegram npm package) to listen for new messages in Telegram groups. The NewMessage event handler works perfectly for: Direct messages (DMs),Small groups (< 1000 members),Medium groups (tested up to ~5000 members) However, it completely fails to fire for large supergroups (30k+ members), even though: My account is a member of these groups I can manually fetch messages using client.getMessages() The listener has been running continuously for 2+ days New messages ARE being sent to these groups (verified manually)

I've Verified Account has access: Using client.getDialogs() shows I'm a member of the group with 31,512 members Can read messages: client.getMessages(groupEntity, {limit: 10}) successfully returns recent messages

const { TelegramClient } = require("telegram"); const { StringSession } = require("telegram/sessions"); const { NewMessage } = require("telegram/events"); const apiId = parseInt(process.env.API_ID); const apiHash = process.env.API_HASH; const stringSession = new StringSession(process.env.SESSION_STRING); (async () => { const client = new TelegramClient(stringSession, apiId, apiHash, { connectionRetries: 5, }); await client.start({ onError: (err) => console.log(err), }); console.log("✅ Connected!"); // This event handler NEVER fires for large groups client.addEventHandler(async (event) => { console.log("📨 New message:", event.message.text); // Process message... }, new NewMessage({})); console.log("👂 Listening..."); })();