Sophos AutoUpdate Status error from the server

Hello,
This is the message that I have every time I want to update Sophos Antivirus and I cannot skip it or make the necessary updates. I tried to make the updates manually and automatically. Is there a solution for this error or should I look out for another antivirus ?
Thank you !

Could not contact primary server
Authentication Error: 18 August 2013 0:34
