After adding a couple of items to a group library, my sync stopped working. It either just kept spinning or I got an "empty response from the server" message. I then deleted all the data on the server -- a foolish thing to do, as I know now. Since then I haven't been able to make the sync work again. I have read the explanations on http://www.zotero.org/support/kb/sync_queuing and in various related threads, but no matter how long I wait, how often I've restarted or if I try sync with or without attachments, I can't make the sync complete. In my latest attempt I got an "empty response from server" message after about an hour of spinning. Report ID is 1075781583. No items show up in my online library. I have a large library of 1296 items and am running the latest versions of FF and Zotero on Windows 7.
Could someone please look into this? Thanks so much!
Harald.

Update: FWIW, the most recent attempt ended with a SSL certificate error. Report ID 1112205687