Auto Update error 71

Hello,

I have a problem with the auto update. I don't modified anything, but yesterday, this problem is arrived on all my computers (servers and users computers). Since yesterday afternoon, I can see an update on the users (a 6 hours update) but not on my servers (in particular in my Sophos management server), this update doesn't work and show the message below :

AutoUpdate finished
Downloading phase completed
ERROR:   Could not find a source for updated packages
Could not connect to the server. Check that this computer is connected to the network and that Sophos AutoUpdate is configured to update from the correct location with the correct credentials and proxy details (if required)
Downloading product Sophos AutoUpdate from server \\server\SophosUpdate\CIDs\S000\SAVSCFXP\
Could not add a connection to server \\server\SophosUpdate; user .; Windows error 71
Could not connect to the server. Check that this computer is connected to the network and that Sophos AutoUpdate is configured to update from the correct location with the correct credentials and proxy details (if required)
Downloading product SAVXP from server \\server\SophosUpdate\CIDs\S000\SAVSCFXP\
Could not add a connection to server \\server\SophosUpdate; user .; Windows error 71
Could not connect to the server. Check that this computer is connected to the network and that Sophos AutoUpdate is configured to update from the correct location with the correct credentials and proxy details (if required)
Downloading product RMSNT from server \\server\SophosUpdate\CIDs\S000\SAVSCFXP\
Could not add a connection to server \\server\SophosUpdate; user .; Windows error 71

***************          Sophos AutoUpdate started          ***************

Thank you.