> ## 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.

# CrossmintConfigurationException

> Flutter Final Class

**Final Class**

Thrown when the client is configured incorrectly — missing API key, invalid base URL, incompatible runtime overrides, etc.

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

## Constructors

### CrossmintConfigurationException

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

Creates a configuration exception.