# Limits & errors

What LINE's Messaging API does not allow, who bills the message quota, and the common errors.

## Message quota

LINE sets a monthly message quota per Official Account and bills it to the account owner, on the plan for its country.

Replies sent with a reply token do not count. Push messages and broadcasts do.

Zernio counts the messages you send on your plan's [message meter](https://zernio.com/pricing#message-rates), like every other channel. LINE's charges never pass through Zernio.

## What you cannot do

- Post to LINE VOOM: LINE has no API for it.
- Read or reply in group chats or multi-person chats (not supported yet).
- Message a user who has not added the account as a friend, or who blocked it.
- Use LINE's auto-response next to Zernio: turn it off, or both answer.

## Common errors

| Error | Cause | Fix |
|-------|-------|-----|
| `400` on connect | Wrong Channel ID or Channel secret | Copy both again from the channel's Basic settings tab. |
| No messages arrive | Webhooks is off, or the webhook URL was changed in the LINE Developers Console | Turn on Webhooks in Settings > Response settings; connect again to restore the URL. |
| Push rejected for quota | The monthly message quota is used up | Upgrade the plan or raise the limit in LINE Official Account Manager. |
| Push rejected for the user | The user blocked the account or never added it as a friend | Nothing to fix on your side. |

## Related

- [Connect](/platforms/line/connect) - Credentials and the two LINE settings
- [Inbox](/platforms/line/inbox) - Reply tokens, push and broadcasts