Google is reporting service issues with Google Drive. Users may get an Error 502 when trying to access Drive. It is possible to access individual documents if you know the URL.
This service interruption only applies to Google Drive and appears to be affecting the consumer Google Drive service as well.
The latest Google status information is here:
http://www.google.com/appsstatus
We will update this alert when we have further information.
– Computing and Communications Services
UPDATE
The issue with Google Drive was resolved at approximately 12:30 PM today, Wednesday June 4, 2014