When StreamLink encounters an error in a subscription it raises an event. To do this it

• creates an ISubscriptionErrorEvent,
• passes the ISubscriptionErrorEvent to the SubscriptionErrorReceived(ISubscription, ISubscriptionErrorEvent) method of the ISubscriptionListener associated with the subscription.

Once the subscription has been requested on the Liberator, an associated ISubscriptionErrorEvent event can be raised at any time, whether or not StreamLink has received any data relating to the subscription.

Situations where an ISubscriptionErrorEvent can be raised before any data is received include:

• There are no DataSources connected to the Liberator and the subject is not already cached within the Liberator.
• The connected DataSources cannot supply data for the requested subject.
• The username supplied by the application does not have sufficient permission to subscribe to the requested data.

Situations where an ISubscriptionErrorEvent can be raised after data is received include:

• The subject has been deleted either by a DataSource or by another a StreamLink client.
• The user’s permission to access the data on the Liberator has been revoked by a Liberator administrator.