User blog comment:FairyRaven/Fairy Tail Chapter 371: Tartarus Arc, Part 2: Song Of The Heavenly Dragon, Review and Commentary/@comment-24546844-20140214145920/@comment-7418318-20140214150738

Cana just said she met that person, she never said where. And at least in the Mangastream verison she said "a while back".

Cana might have met him when she was out of town on some errand or mission. For all we know she might have had to travel to the other side of Fiore for a mission and met him there.