I can't add foreign key constraint in Laravel
You must follow the same datatype with unsigned for foreign key. By default laravel uses bigint so you must use unsignedBigInteger
Schema::create('chats', function (Blueprint $table) {
$table->id();
$table->unsignedBigInteger('from_id');
$table->unsignedBigInteger('to_id');
$table->text('message');
$table->foreign('from_id')->references('id')->on('users');
$table->foreign('to_id')->references('id')->on('users');
$table->timestamps();
});