The png file is spelled wrong. If you rename the file with a 1 in the end instead of 0 it works. LunarLandscape_Content_001-1.png. Hope this helps someone.
It helped me fixing the problem to the core :) Thanks! I updated the package, the texture is now correctly named and should appear correctly. Reach out to me via email, I'd like to offer you a gift for helping the community out!