Laravel 8 - ErrorException Undefined array key 25 in file /vendor/laravel/framework/src/Illuminate/Foundation/helpers.php on line 1223

The error message "ErrorException Undefined array key 25" in Laravel 8 indicates that an array index that is being referenced does not exist. In this specific case, the error is occurring in the Illuminate\Foundation\helpers.php file, which is part of the Laravel framework.

The line number mentioned in the error message is 1223. This line of code is responsible for accessing an array key based on a value from another array. Here's a snippet of the code:

if (isset($this->app['config']['app.key'])) {
    $key = $this->app['config']['app.key'];
} else {
    $key = $this->app['config']['app.debug'] ? config('app.debug_key') : str_random(32);
}

$key = array_get($this->app['config'], 'app.key', $key);

The array_get() function is used to retrieve a value from an array using a key. In this case, the key is 'app.key'. However, if the 'app.key' key does not exist in the array, then an undefined array key error will be thrown.

To fix this error, you need to ensure that the 'app.key' key exists in the config/app.php file under the 'app' array. Here's an example of what the 'app' array should look like:

'app' => [
    'key' => env('APP_KEY'),
    // other keys...
],

Make sure that the APP_KEY environment variable is set in the .env file as well:

APP_KEY=base64:your-key-here

After making these changes, clear the Laravel cache by running the following command in your terminal:

php artisan cache:clear

This should resolve the "ErrorException Undefined array key 25" error in Laravel 8.