All my work keeps disappearing. Am on my second Ukrainian challenge. Have spent hours. But it says I haven't learned any words

All my work keeps disappearing. Am on my second Ukrainian challenge. Have spent hours. But it says I haven’t learned any words.

At the moment you have 526 Known words in Ukrainian and 516 LingQs created. What exactly doesn’t work for you? You have added 46 words to Known today created 37 LingQs. Everything seems fine. Can you please explain a bit more what exactly doesn’t work properly?