API Resource Collection - How use realtionship?

Hello!

In my REST API I have a Sale Resource and DeviceInspection Resource and I need use data from Sale in DeviceInspection for display records. I trying like this but this is not work :-( Where I make a mistake?

Sale model

<?php

namespace App;

use Illuminate\Database\Eloquent\Model;
use Illuminate\Database\Eloquent\SoftDeletes;
use App\DeviceInspection;

class Sale extends Model
{
    use SoftDeletes;
    protected $fillable = [
        'user_id', 
        'sales_number', 
        'customer_institution', 
        'institution_address', 
        'product_name', 
        'manufacturer', 
        'serial_number', 
        'amount_of_sales', 
        'sale_date', 
        'guarantee_period', 
        'directory_link',
    ];
    public function inspection() {
        return $this->hasMany(DeviceInspection::class);
    }
}

Device Inspection model

<?php

namespace App;

use Illuminate\Database\Eloquent\Model;
use Illuminate\Database\Eloquent\SoftDeletes;
use App\Sale;

class DeviceInspection extends Model
{
    use SoftDeletes;
    /**
    * The atributes that should be muted to dates.
    *
    * @var array
    */
    protected $fillable = [
        'sale_id',
        'inspection_date',
        'service_man',
        'status'
    ];
    protected $dates = ['deleted_at'];
    
    public $sortable = ['created_at'];
    
    public function sale()
    {
        return $this->belongsTo(Sale::class);
    }
}

Sale Resource

<?php

namespace App\Http\Resources;

use Illuminate\Http\Resources\Json\JsonResource;

class Sale extends JsonResource
{
    /**
     * Transform the resource into an array.
     *
     * @param  \Illuminate\Http\Request  $request
     * @return array
     */
    public function toArray($request)
    {
        return [
            'id' => $this->id,
            'sale_number' => $this->sale_number,
            'user_id' => $this->user_id,
            'customer_institution' => $this->customer_institution,
            'institution_address' => $this->institution_address,
            'product_name' => $this->product_name,
            'manufacturer' => $this->manufacturer,
            'serial_number' => $this->serial_number,
            'amount_of_sales' => $this->amount_of_sales,
            'sale_date' => $this->sale_date,
            'term_realization' => $this->term_realization,
            'guarantee_period' => $this->guarantee_period,
            'directory_link' => $this->directory_link,
            'file_sales' => $this->file_sales,
            'sale_type' => $this->sale_type,
        ];
    }

    public function with($request) {
        return [
            'version' => '1.0.0'
        ];
    }
}

DeviceInspection Resource

<?php

namespace App\Http\Resources;

use Illuminate\Http\Resources\Json\JsonResource;

class DeviceInspection extends JsonResource
{
    /**
     * Transform the resource into an array.
     *
     * @param  \Illuminate\Http\Request  $request
     * @return array
     */
    public function toArray($request)
    {
        return [
            'id' => $this->id,
            'sale_id' => $this->sale_id,
            'inspection_date' => $this->inspection_date,
            'service_man' => $this->service_man,
            'status' => $this->status,
            'warranty_service' => $this->warranty_service,
            'created_at' => $this->created_at,
            'updated_at' => $this->updated_at,
            'sale' => Sale::collection($this->whenLoaded('sale'))
        ];
    }

    public function with($request) {
        return [
            'version' => '1.0.0'
        ];
    }
}

And my API Controller method show

/**
     * Display the specified resource.
     *
     * @param  int  $id
     * @return \Illuminate\Http\Response
     */
    public function show($id)
    {
        return new DeviceInspectionResource(DeviceInspection::with('sale')->findOrFail($id));
    }

And when I try to get data from API by postman receives an error:

Symfony\Component\Debug\Exception\FatalThrowableError: Call to a member function first() on null in file C:\xampp\htdocs\Customer-Service_v_2.0\vendor\laravel\framework\src\Illuminate\Http\Resources\CollectsResources.php on line 24

How fix this??

Thanks