The hub not updating sites

I have several sites on the hub, which I'm trying to automate upgrades and backups

it seems some sites update fine while others immediately fail with the error

cURL error 51: SSL peer certificate or SSH remote key was not OK

ive had a discussion a while back about this and support asked me to get hold of my host to see if openssl or cURL was out of date, they didn't see an issue.

also I have several sites on the same webserver with my host, some work and some don't and they are on the same server