The world wide web has been dragging lately. I would have to presume it is due to a lot of traffic. If you have been looking at websites lately, the pages load slow or not at all with errors. Ebay search doing the same thing yesterday for me.
The only other thing it can be is that your auction profiles have errors and you can check that at the bottom of each auction. Mine used to do it off a master profile, simply for something like not selecting the kind of shipping packaging type.