what has happen is that the address http://forum.gn15.info/ does no longer work as it should !! (menus works, but not threads).
instead start with http://gn15.info/forum/ and voila, back to normal ..
note the difference in above addresses. The word forum should be at the end instead of before. In computer lingo, the sub-domain has changed into a folder instead.. Strangely enough I found notes about this dated back at 2014-12-08 .. so during a period both starts for the site must have been active .. and just recently the first link above got "partly" broken in the sense that view-topic no longer works ..
ps! this is a copy of a previous message for those who only knows about the first address above. Hopefully they at least see the title to this thread.