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

# CrossmintSignerException

> Flutter Final Class

**Final Class**

Thrown by signer operations — missing host, rejected OTP, unsupported export, missing passkey callback, upstream signer-service errors.

```dart theme={null}
final class CrossmintSignerException extends CrossmintException
```

## Constructors

### CrossmintSignerException

```dart theme={null}
const CrossmintSignerException(
  super.message, {
  super.code = CrossmintErrorCode.unknown,
  super.cause,
})
```

Creates a signer exception.