How long before a message expires from the held queue?

The expiration period for messages held in the Mimecast queue is set at 14 days. This duration is designed to balance the need for retaining emails long enough for potential review or retrieval while also ensuring that the systems are not burdened with excessively old messages. In practice, after a message has been held for 14 days, it is automatically purged from the queue, which helps maintain system efficiency and reduces clutter. This standard expiry timeframe reflects common industry practices for managing held email messages.