Which engine do you use ?
Whith godot for exemple you need to make a specific export for linux.
Viewing post in Waningdale
Well i don't know Unity but you need to have another type of file than .exe (which is windows only).
Typically any extension (because linux doesn't care about extesion) like x86_64 for exemple
Arf do you have more info ? Where is it flagged ? What does it says ? I made it using godot should be fine ...