As mentioned in this dev update (about one month ago), several virtual servers on which the alpha nodes were running had shut down (for some reason, about 20-25 of the 100 droplets running the alpha network had gone through a upgrade/power cycle) and we had to restart the nodes on those rebooted servers. Some data has been lost, which explains why you are unable to access most of the sites listed on https://wgallo3.github.io/AlphaDirectory/.