I’ve got a yahoo email and have the same issue with not being able to receive authentication emails. Password reset emails also don’t arrive. The last email I received was on November 13th at 12:08AM about the Tower of Nightmares content from guildwars2@ncsoft.com.
I was able to receive an invitation email to the Edge of the Mists alpha, but there’s an issue with the alpha team sending me my login credentials. I suspect that issue is the same reason why authentication emails don’t come through to me. The EotM emails I received were from the arena.net domain, and authentication emails have always come from a @guildwars2.com email.