Alert.alert not working for IOS in react native

I have used Alert.alert with ok button (on ok button click have added redirection) in react native. Its working fine on android but on IOS Alert shows but its getting closed immediately.

Alert.alert(  
        'Alert Title',  
        'My Alert Msg',  
        [   
            {
              text: 'OK', onPress: () => {this.props.navigation.navigate('Dashboard')}
            },  
        ],
        { cancelable: false }
    );