---
title: World Connection Failure 4216 What is error code?
slug: world-sdk-guide/world-connection-failure-4216-what-is-error-code
docTags: 
createdAt: 2024-09-02T08:34:13.136Z
---

The 4216 error that occurs during World play occurs when there is an error in the server code you created.

- Please try to find the error in your onCreate / onJoin / onLeave or Message Event and fix it.
- It is recommended to use Nullable or try-catch syntax to resolve issues with code stability and exception handling.

Please check the caveats for writing server code.

:::hint{type="info"}
**📘 **Please refer to the following guide. [\[Precautions when using server code\]](docId\:ApiJZlMSeJHbGIuPwsMdm) 
:::