Hi. I'm David, and I'm happy to help you.
While a "took too long to respond" error on this website definitely feels like a firewall block, it is very often triggered by active VPNs or cached browser data that the website's security systems flag. Running a couple of quick checks first is the easiest way to rule those out before changing any advanced network settings:
Please see if the same behavior occurs in an InPrivate/Incognito window. To open the InPrivate/Incognito window, open the browser and press "Ctrl + Shift + N". (For Microsoft Edge and Google Chrome)
If this also happens in the InPrivate/Incognito window, can you tell me if you have any VPN software installed? (Even if it's not running at the moment) If yes, which one?
Looking forward to your reply.