Why does my Laravel app show "500 | Server Error"?

A 500 means an uncaught exception was thrown and APP_DEBUG=false hid the detail. The real error is in storage/logs/laravel.log, common causes are a missing APP_KEY (No application encryption key has been specified), a stale config:cache after deploy, a database connection failure, or a thrown HttpException. We read the actual trace, fix the cause, and make sure debug mode is safely off in production afterward.