Https://buy.norton.com/... - NOT SECURE?

Lyngby, DK, 28.12.2014 (2nd posting ... as the first is not visible in the "Other Norton Products" forum thread)

On the web page https://manage.norton.com/ManagementHome is a link with the title "Do you want more Norton" (translated from danish, see attachment "More Norton"). Clicking this I get a web page https://buy.norton.com/... with the message (see attachment "Web site ID not confirmed") telling me that the web site ID could not be confirmed and a secure connection cannot be established. (The security certificate is invalid, error code: sec_error_unknown_issuer).

I find this rather strange for company in the anti-virus/-malware etc. business.

What shall I do? I use FireFox 29.0.1 in Windows 7 SP1.

Regards
Claus Alsted