Since the recent transfers, the overall quality of service of those servers has been an issue. In an effort to increase stability, servers will go down for a brief two-hour maintenance window.
Quote from BioWareWe will be performing an unscheduled maintenance this Wednesday, July 4th, 2012. This maintenance will increase server stability. After the maintenance, there will not be a new patch to download.
This evening, we will be bringing down the game servers and SWTOR.com for a brief maintenance period for two hours from 2AM CDT (12AM PDT/3AM EDT/8 AM BST/9AM CEST/5PM AEST) until 4AM CDT (2AM PDT/5AM EDT/10AM BST/11AM CEST/7PM AEST). All game servers and SWTOR.com will be offline during this period. This maintenance is expected to take no more than two hours, but could be extended.
For the post in full, head on over to the official thread.