"Are you in Barra, Ewan?"
Translation:A bheil thu ann am Barraigh, Eòghainn?
Probably Duolingo not being able to distinguish between the grammar cases.
Eòghann is the spelling when talking about someone called Euan, Eòghainn is the spelling when talking to someone called Euan (vocative case). Normally there is also an a and a h added to the beginning of the word (for example, a Sheumais), but as Eòghann begins with a vowel it doesn't get that.