Guildwork apparently can't find my character on offical servers, and hasnt been able to for almost 2 weeks now, so hasn't updated at all since then... Something to do with the site being almost constantly down?
Yeah there was a window where Guildwork was working correctly but as of right now it's 500 erroring again. Once Rooks fixes it again, you shouldn't have trouble linking your Guildwork to your Character and your FFXIAH account if you so choose.
Hope that helps.