# IFatalErrorHandler.OnFatalException(object?, string?, Exception?)

[Type overview](/orleans/docs/api/csharp/microsoft.orleans.runtime/orleans.runtime.ifatalerrorhandler/) | [Methods](/orleans/docs/api/csharp/microsoft.orleans.runtime/orleans.runtime.ifatalerrorhandler/methods/)

```csharp
public abstract void OnFatalException(object? sender = null, string? context = null, Exception? exception = null)
```

Called when a fatal exception occurs.

### Parameters

- `sender` (`object?`): The sender.
- `context` (`string?`): The context.
- `exception` (`Exception?`): The exception.