We're currently experiencing a technical issue with a part of our ad system. AdWords ad serving has not been affected. Your ads will continue to show as per your campaign settings, and your AdWords statistics will continue to update normally. However, you will be unable to access your AdWords account to view your campaigns or make changes at this time.
We're working on a solution and we apologize for any inconvenience this may cause you. Please check our known issues page for updates.