Hello, Daisuke Tanaka!
Usually, there's an issue with a plugin that doesn't work properly. The "Encrypt assets" option also turns on the option compile the game's source code, which can break some plugin (usually it's because they try to dynamically find their name via document.src). You can check for errors by enabling the option "Create a test build" on the Project Settings -> Essentials tab. Once it's created, run the game and press F12 to open the dev tools. If they don't open, remove the --disable-dev-tools command line argument on the package.json file.