# SignalRegistrationError
<span class="source-link">[[Source]](src/signals/signal_notify.md#L-0-18)</span>

Why a `SignalHandler`'s registration could not be completed.


```pony
type SignalRegistrationError is
  (SignalSubscriberLimit val | SignalRegistrationRefused val)
```

#### Type Alias For

* ([SignalSubscriberLimit](signals-SignalSubscriberLimit.md) val | [SignalRegistrationRefused](signals-SignalRegistrationRefused.md) val)

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