I have not encountered this problem in awhile but I just happened when going to the forums (but not on the main webpage). I copied the console output from the debug console when it happened. Maybe this can give some information as to what is happening.
Console Output:
HTML1300: Navigation occurred.
ironcrown.com (1,1)
HTTP406: NONE ACCEPTABLE - No responses acceptable to the client were found.
GET - http://ironcrown.com/wp-content/plugins/catalog/spiderBox/spiderBox.js.php?delay=3000&allImagesQ=0&slideShowQ=0&darkBG=1&juriroot=http%3A%2F%2Fironcrown.com%2Fwp-content%2Fplugins%2Fcatalog&spiderShop=1&ver=4.9.10
2HTML1509: Unmatched end tag.
ironcrown.com (253,163)
JQMIGRATE: Migrate is installed, version 1.4.1
HTML1521: Unexpected "</body>" or end of file. All open elements should be closed before the end of the document.
ironcrown.com (525,1)
HTML1300: Navigation occurred.
index.php (1,1)
HTML1524: Invalid HTML5 DOCTYPE. Consider using the interoperable form "<!DOCTYPE html>".
index.php (1,1)
SEC7115: :visited and :link styles can only differ by color. Some styles were not applied to :visited.
index.php (1,1)
HTML1300: Navigation occurred.
index.php (1,1)
HTTP500: SERVER ERROR - The server encountered an unexpected condition that prevented it from fulfilling the request.
GET - http://www.ironcrown.com/ICEforums/index.php?board=162.0