Cannot find 'dusklight' package

Greeting into the forum! I have two systems, which do only differ in hardware. All other configuration is the same. When providing the package dusklight on one system via `nix-shell -p dusklight` it works, on the other system I get the message `error: undefined variable ‘dusklight’`. The expected outcome is that the dusklight binary is available in the shell. How can I troubleshoot this issue? What informations do I need to gather to fix this issue? Thanks in advance, for beginner help! EDI...