MapView doesn't render map

Created by: horseunnamed

I'm trying to use examples from this repository. Only change I made is replace MAPKIT_API_KEY constant at activities to my api key. But MapView doesn't render map, only empty grid is shown. I'm not sure is it problem with my api key or with library. And don't see the way how to distinguish these cases (found no logcat messages related to this issue). Tested at several devices with various android versions (api 21, 27, 28).