Seems that we've found source of our problems. We've noticed that were getting at least 5 requests per second from IP address 68.58.188.236 to "index.php?act=rssout&id=1". Now, this is no longer a valid page in IPB3 (was in IPB2 however, although it was off too), but the fact that there are like 5 requests per second from the same IP means that our server was basically getting flooded with requests and just couldn't handle it. Upon editing .htaccess file to block this IP address load dropped from 16 to 2.22.. The problem was either we were being DOS'd by the IP mentioned above, more or less or it was a valid member who simply has a buggy RSS reader (and that RSS reader has the old invalid URL in it for our RSS feed). We should figure out which members can no longer access our site, let them know about the issue, so they can update the URL for the RSS feed in their reader, which should likely resolve the problems (when they could be unblocked again). Note to members: Please remove any RSS links you are using for WinCert.net Forum.