-- What are the reasons for the Gateway mailbox to grow beyond a pre-allocated space of 2GB?

* There are a number of reasons why the mailbox can grow. These include:

1. Transfers older than a set number of days being stored in the mailbox
2. Transfers are not purged frequently enough
3. The volume of daily transfers may have grown
4. The initial size of the mailbox was too small and did not account for transfer storage and growth.