"There is a problem with this website's security certificate" Download Page

Hi everybody, today I was trying to download Knime in a customer´s PC and when I clicked the "accept the terms and conditions" option, the Internet Explorer showed me: "There is a problem with this website's security certificate".

I wonder why that is happening?

Thank you

Maybe your customer is using a proxy/firewall that messes with encrypted traffic?

Thank you Thor I will ask them 

Best Regards