Thank you for providing that link. That would explain the error. I don't have any extensions changing the url, I am however in Europe (Sweden) which probably allocates me towards different mirrors.
I will make sure that the mirror url provided by eclipse is not affected by anything on my setup, and if that's the case report it to the Eclipse foundation.
Google chrome having a market share of 66 % blocking a secure website (seemingly arbitrarily) is at least problematic.