PushTopic Streaming Allocations
If you exceed the default event delivery allocation, you receive this error: 403::Organization total events daily limit exceeded. The error is returned in the Bayeux /meta/connect channel when a CometD subscriber first connects or in an existing subscriber connection. For more information, see Streaming API Error Codes. PushTopic event notifications that are generated after exceeding the allocation are stored in the event bus. You can retrieve stored event messages as long as they are within the retention window of 24 hours.
If you have scenarios that warrant an increase in the number of delivered event notifications within a 24-hour period, contact Salesforce.