Well guys I think I figured out what might be the issue. My account was registered a year ago and as far as I remember, there was no slice machine at that time. Yesterday I tried to register a fresh account in Prismic, and follow the same exact steps -- everything worked like a charm. But this is really strange to me, and unfortunately I spent like a day just in vain trying to figure out if I do something wrong. If you want to perform some debugging, my "old" account's repo is fbjorn, and fresh one (tied to second account) is fbjorn123. I'd still appreciate some information regarding this issue if possible.