We have temporarily disabled access to the Black Lion Voucher Vendor while we address an issue. We will re-enable the NPC as soon as the issue has been resolved. In the meantime, you can continue to make voucher exchanges through the normal means. A full list of items available through Black Lion Vouchers can be found on the Guild Wars 2 wiki.
Communications Manager: ArenaNet
Fansite & Guild Relations; In-Game Events; Community Showcase Live