SparkManager::toPlans(): ($config) must be of type array, null given

Hi, I am using Laravel 10 with spark-stripe v5.0. When I try to subscribe I get a technical error:

Whoops! Something went wrong. An unexpected error occurred and we have notified our support team. Please try again later.

This is the error in laravel.log file:

Spark\SparkManager::toPlans(): Argument #1 ($config) must be of type array, null given, called in D:\Lab\Projects\web\vendor\laravel\spark-stripe\src\SparkManager.php on line 243

Spark.php File

Billables array in Spark.php configuration file:

'path' => 'user/billing',
'middleware' => ['web', 'auth'],
'brand' =>  [
        'logo' => realpath(__DIR__ . '/../public/images/fashy-logo.svg'),
        'color' => '#D84B5B',
],
'prorates' => false,
'features' => [
        Features::paymentNotificationEmails(),
],

'billables' => [
        'user' => [
            'model' => User::class,
            'default_interval' => 'monthly',
            'plans' => [
                [
                    'name' => 'Subscription',
                    'short_description' => 'Test Description',
                    'monthly_id' => env('STRIPE_MONTHLY_PRICE'),
                    'yearly_id' => env('STRIPE_YEARLY_PRICE'),
                    'features' => [
                        'Full access to our discounts',
                    ],
                ],
            ],
        ],
    ],

User Modal File

class User extends Authenticatable implements MustVerifyEmail
{
    use HasApiTokens;
    use HasFactory;
    use HasProfilePhoto;
    use Notifiable;
    use TwoFactorAuthenticatable;
    use Billable;
    use SoftDeletes;

    /**
     * The attributes that are mass assignable.
     *
     * @var string[]
     */
    protected $guarded = [];

    protected $casts = [
        'email_verified_at' => 'datetime',
        'trial_ends_at' => 'datetime',
        'dob' => 'date',
    ];

}

Any help would be appreciated! Thanks