> ## 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.

# E1212 — Unsupported instruction/opcode

> Unsupported instruction/opcode

# E1212 — Unsupported instruction/opcode

| Property     | Value                     |
| ------------ | ------------------------- |
| **Code**     | `1212`                    |
| **Slug**     | `E1212`                   |
| **Category** | `validation` (Validation) |

## What happened

Unsupported instruction/opcode.

## Why it happened

The actor code contains an instruction or opcode not supported on this chain version.

## How to fix

Use a supported instruction. Check the chain version's compatibility documentation.

## Receipt example

```json theme={null}
{
  "code": 1212,
  "slug": "E1212",
  "category": "validation",
  "what": "Unsupported instruction/opcode",
  "fix": "Use a supported instruction.",
  "docs_url": "https://docs.cowboy.inc/errors/E1212"
}
```

***

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