Defender wont update on windows 10

Defender on my main machine wont update saying a network problem yet my other machine on the same network is up to date, anyone know a fix?

See if these help
https://support.microsoft.com/en-us/kb/918355
http://www.microsoft.com/security/portal/definitions...

As if by magic it has fixed itself after a reboot.

Standard computer maintenance procedure - switch it off and switch it on again.

In reply to a post by micksharpe:

Standard computer maintenance procedure - switch it off and switch it on again.

Reminds me of the Rule of thumb mainframe engineers had in the seventies - run the back of your thumb across the backs of the PCBs.

Amazing what a nudge to the seating of the edge connector would do to get things working again

Ive come to realise over many years working on computers that they often do things no amount of logic can fathom out and a reboot is usually the best cause of action