# Internal Exception

## First fix

Try to update to the latest ProtocolLib and if you use ViaVersion also update it.

## Second fix (if required)

`Internal Exception: io.netty.handler.codec.DecoderException: java.lang.IndexOutOfBoundsException: index: 5, length: 13632 (expected: range(0,30))`

![](https://2228257718-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2Faipc4QQKwVS0w1Q604ya%2Fuploads%2Fgit-blob-59538fb9b4747150f570e267cf502d949b11b375%2Fimage%20\(48\).png?alt=media)

Open `config.yml` of **ItemsAdder** and change this value to `false`: `optimized-packets: false`

{% code title="config.yml" %}

```yaml
  custom-entitites:
    optimized-packets: false
```

{% endcode %}