ACX check

Hi, I am using audacity on windows 8.1. i have been using the ACX checker quite happily for about 12 months now, and it has suddenly stopped working. when i use it the dialogue box pops up ans says checking is complee and then … nothing, no results, sometimes it says it is not responding. It has worked perfectly well up until now. any ideas?

sorry, it is version 2.4.1