There are currently two editions of Minecraft being actively developed:
- Java Edition - Available for Windows, Mac, Linux
- Bedrock Edition - Available for Windows 10 (UWP app on the Microsoft Store), Android, iOS, Xbox One, etc.
The players on the Java Edition can only connect to Java Edition servers, and the players on the Bedrock Edition can only connect to Bedrock Edition servers. (The platform / OS which on the game is running doesn't matter, except in the case of Xbox One, where there are some limitations for players without Xbox Live Gold.) You need to download the appropriate server for your edition.
Alternatively -, but this is not (yet) a good option - you can run a Minecraft: Java Edition Spigot server, which is an (indirect) fork of the original vanilla Minecraft server with some tweaks and support for plugins, install the ProtocolSupportPE plugin to allow Bedrock Edition players to connect to your Java Edition server. Please note that this is in heavy development, you will have to compile it yourself, and last time I've checked it out, it had a major bug with you not being able to see the player at the right location, but as time goes by, this solution might become reasonable, but I have referenced it in case somebody really needs it.