The Silk Road has been notoriously unreliable. Constantly "Down for maintenance" and often just unresponsive for hours at a time. Besides the government it has also come under a number of malicious attacks from disgruntled users.

I imagine the DPR was logging in via VPN just to get some kind of consistent access to the site, even with I'm sure there were many times where the servers were unresponsive even to him.