> ## Documentation Index
> Fetch the complete documentation index at: https://docs.cowboy.inc/llms.txt
> Use this file to discover all available pages before exploring further.

# E1205 — Operation forbidden

> Operation forbidden

# E1205 — Operation forbidden

| Property     | Value               |
| ------------ | ------------------- |
| **Code**     | `1205`              |
| **Slug**     | `E1205`             |
| **Category** | `runtime` (Runtime) |

## What happened

Operation forbidden.

## Why it happened

The operation is disallowed in this context. Common triggers: synchronous call depth exceeding 32, reentrant call detected, or side-effect in a `@pure` handler.

## How to fix

Restructure the call graph — flatten the call chain, use asynchronous messages instead of deep sync calls, or move side-effects out of `@pure` handlers.

## Receipt example

```json theme={null}
{
  "code": 1205,
  "slug": "E1205",
  "category": "runtime",
  "what": "Operation forbidden",
  "fix": "Restructure the call graph — flatten the call chain, use asynchronous messages instead of deep sync calls, or move side-effects out of `@pure` handlers.",
  "docs_url": "https://docs.cowboy.inc/errors/E1205"
}
```

***

<Card title="All Error Codes" icon="list" href="/errors/overview">
  View the complete error code reference
</Card>