Upload a file edited by POedit back to transifex

Hi there!
Im trying to upload a file i edited with POedit back to transifex.
I click the “master-cataclysm-dda” branch in my language, then “Upload a file” and i chose the edited .po file i saved on my pc.
But the file won’t upload, this screen is there all the time. No error…
What am i doing wrong?

I’m thinking about purchasing a Pro+ licence to do a large amount of translation for the game.
But not if i can’t upload the file i translate,