Geekspeak I don't understand

[Roland Perry]

In article <20150513123103.GA25424 at unequivocal.co.uk>, Jon Ribbens 
<jon+ukcrypto at unequivocal.co.uk> writes
>> or what's amiss in 'my setup'?
>>
>> "An error occurred during a connection to www.facebook.com. The server uses
>> key pinning (HPKP) but no trusted certificate chain could be constructed
>> that matches the pinset. Key pinning violations cannot be overridden. (Error
>> code: mozilla_pkix_error_key_pinning_failure)
>>
>>     The page you are trying to view cannot be shown because the
>>     authenticity of the received data could not be verified.
>>
>>     Please contact the website owners to inform them of this problem."
>
>Is it a corporate computer or similar that might have a root
>certificate installed by the IT department?

No, it's my five year old laptop where only I am the administrator.

Not sure if it matters but about three months ago I wiped the 
Win7-upgraded-to-Win8 installation and did in effect a "factory reset" 
back to Vista.

I use Facebook multiple time most days (for years), and have never 
before seen any error message like this.
-- 
Roland Perry