SpamAssassin Cron error


I’ve been receiving this message from cron, every day (to my root mailbox):

channel: could not find working mirror, channel failed
sa-update failed for unknown reasons

It’s a new install (about 10days old) on ubuntu 14.04.

I’ve looked in /var/log/ for a log that might be related to SpamAssassin and found nothing, unfortunately. /var/log/cron.log is empty.

I’ve tried running sa-update manually (as root) & it seems to run ok, so I’m not sure what cron is whining about.

Has anyone else seen this?
Any idea on where I might be able to start looking for solutions to the problem?

(I’m a bit n00b-ish, but willing to learn)