So you can't connect to the website? did you try clearing cache, history, cookies, all the basic first?
Then try flushing your cache
Type dscacheutil -flushcache in to your terminal.
If none of that works, try adding it to your secure sites with your web browser, also make sure encryption is enabled in your options, otherwise as far as I know, you won't be able to connect to a encrypted site. But I very much doubt that's the reason.
Then reply to let me know if it works. 🙂