It looks like the character was deleted a few days ago. There were a few characters deleted around the same time (a level 70 Lightforged Draenei Paladin and level 60 Dracthyr Evoker), so you may have been doing a little clean up and deleted that one by mistake.
Unfortunately, the Undelete option is currently disabled while some issues with restoring characters is addressed. We don’t have an estimate on when it will return, but we do hope soon in an upcoming patch.