I can't find my presentation in Prezi Explore... Why?

Hello,

here my problem : I can’t find my presentation in the searchbox (in Prezi)… Why?

I have a presentation with this title “Domino Werbeagentur - Digitale Welten”
When I’m searching ,for example “Domino Werbeagentur”, in the searchbox, I can’t find it. But when I’m searching for “Digitale Welten”, then I find it… Why? 
Can we decide somewhere the keywords?
And in Google it’s the same problem…

Can you help me? 
Thank you per advance and sorry if my english is bad…
Laurent