It's related to the extended downtime a few months back. Without going into too much detail, it also resulted in some people being IP blocked by the firewall due to trying to access the site too frequently.
Unfortunately, the site's owner is the only one who can fix that. If you know how to contact him directly, that would be a good option; otherwise, you'll have to PM one of the moderators
with your IP address so that it can be unblocked, since I'm assuming that you connected via a different means than normal to be able to post this message.