Some clients not live updating

Hi all,

I have a very small system - around 250 clients and some of them - with nothing in common that I can see, some Windows 7, some Windows 10 machines are not live updating.  All are running the same version of SEP 12.1.6.  Live update works if I do it manually, but there's about 45 that need doing and I'd like to figure out why SEPM isn't able to make them update.

All the index2.xml files are current as of today and all the machines are on the same subnet, so the firewall shouldn't be an issue.

I have attached a log file from one of the clients that I got using sylink monitor when I tried to push "Update Content" manually.

Any help would be appreciated.

Vicki