Safari on macOS cannot verify certificate and load pages correctly - it all works in Firefox though?
I run macOS Sierra 10.12.1 on my MB Pro and iMac (2013/14 model). On my iMac, I recently started having issues with accessing the webpages of the Guardian (guardian.co.uk) and the Financial Times (FT.com). It takes some time to load the website and I then get a message saying "Safari can't verify the identity of the website..." When clicking on the website it asks me to validate an ssl.fastly.net certificate both. This is similar for Guardian and FT. I have tried everything from clearing the cache in the Develop menu, disabling extension and plug-ins, clearing all history and website data, ensuring the time stamp is set automatically and locate the certificate in the keychain (cannot find something or the guardian at all). I have finally trusted the certificate for the guardian (not the FT), but the website still loads incorrectly with many images not shown and replaced by blue question marks (see second screenshot).
I am at the end of my wisdom, especially as my MB Pro does not have the issue and loads the pages fine in Safari, and since both Firefox and Chrome do not have any issues with those pages on the very same iMac. I have always used Safari as my preferred browser and would therefore would like to fix this. Any ideas would be great!
Thanks
T