Website Security Certificate issue on domain
When users try to visit a site, www.esinet.ie, they're getting an error: There is a problem with this website's security certificate. It's the same in IE, Firefox and Chrome. Firefox tells me the certificate expired in September. I was testing in a VM that had never visited the site before and there's no proxy in the school.
When I visit using my own laptop, i.e. not joined to the domain, I can view the site without problems and the certificate is still in date.
I went into WSUS and made sure everything IE/Root Certificate related was approved and the computers have run Windows Update, but this didn't fix it.
I had a look in Internet Options/Content/Certificates but didn't see anything that looked unusual. Does anyone know what's going on?