Classifieds translation doesn't work…

Hi,

I copied Classifieds language file (classifieds-default.po) and gave it language extension, as I always do when I translate.
With poedit, now I have .po & .mo files with my language extension.
But… somehow it seems that it doesn't work:
I had translated few strings and nothing happened. It didn't affect the text and no translation is displayed.
(WP5.1 Classifieds 2.3.2)
What's wrong?

Naomi