The only things I can think of are your ISP had networks issues, your local network had connection issues or your browser's cache was invalid or corrupt.
We have a lot of users here who use MacOS, Windows, Linux, iOS, Android, etc., including myself, without any issues.
Next time try a different browser than whatever she normally uses.
If that doesn't work, shut down the computer and while it is off, go find the internet modem/router and turn it off for 30+ seconds (at least 30).
Then turn the modem/router back on, and the computer, but do not attempt to go to CZ yet.
Wait until you can access another site and visit several pages on that site (the home page of the test site may be cached and you may not really be connected to it).
One you can access and visit several pages on another site, try again to access CZ.
If that does't work, then you need to clear your browser cache (while no windows/tabs are on CZ), then reboot your computer (without going to CZ after clearing the cache) and then when it comes back up, see if you can access the site.
