golang function returns empty slice when slice length more than 700 item

I have a function calls API to get items and return items to sync with another db. I can specify limit of items that returns. If the limit is 700 it return 700 item. if more than 700 it return empty slice.

func (d *dataBaseWriterImpl) WriteProducts() error {
	username := os.Getenv("USERNAME")
	password := os.Getenv("PASSWORD")

	// get token
	token, err := d.authService.Login(username, password)
	if err != nil {
		return err
	}

	// load products
    // here the problem if count more than 700 <----
	products, _ := d.scrapperService.LoadProducts(702, 1, token)
	log.Printf("products count -> %d", len(products)) // gives me 0 <-----

	errChan := make(chan error, 2)
	var cats []models.Category
	db.Conn.Model(&models.Category{}).Find(&cats)
	var catIds []string
	for _, cat := range cats {
		catIds = append(catIds, cat.ExternalId)
	}

	for _, prod := range products {
		if d.isValidProduct(catIds, prod.PrimaryVariant.CategoryID) {
			log.Printf("update id -> %v", prod.PrimaryVariant.ID)
			go d.saveOrUpdateProducts(prod.PrimaryVariant, errChan)
		} else {
			log.Printf("will not update id -> %v", prod.PrimaryVariant.ID)
			go func() {
				errChan <- nil
			}()
		}

	}
	for range products {
		err := <-errChan
		if err != nil {
			return err
		}
	}
	return nil
}

I log items length before return it return the actual value in the LoadProducts implementation.

func (s serviceImpl) LoadProducts(count uint, page uint, token string) ([]models.VariantsResult, error) {

	jsonBody := []byte(fmt.Sprintf(`{"pageSize": %d, "page": %d, "sortBy": "updatedAt"}`, count, page))
	body := bytes.NewBuffer(jsonBody)

	// Create request
	req, err := http.NewRequest("POST", fmt.Sprintf("%v/api/variantGroups/search", os.Getenv("BACKEND")), body)
	if err != nil {
		log.Print(err)
	}
	// Headers
	//req.Header.Add("User-Agent", "Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:84.0) Gecko/20100101 Firefox/84.0")
	req.Header.Add("Accept", "application/json, text/plain, */*")
	req.Header.Add("Authorization", fmt.Sprintf("Bearer %v", token))
	req.Header.Add("Content-Type", "application/json")

	// Fetch Request
	resp, err := s.client.Do(req)

	if err != nil {
		fmt.Println("Failure : ", err)
	}

	//[]models.Product `json:"data"`
	// Read Response
	type Response struct {
		Results []models.VariantsResult `json:"results"`
		Count   int                     `json:"count"`
	}
	var response Response

	err = json.NewDecoder(resp.Body).Decode(&response)
	log.Printf("products -> %d", len(response.Results)) // gives me actual number <--
	if err != nil {
		return nil, err
	}
	return response.Results, nil
}

Almost certainly you are returning an error, but then ignoring it.

> A nil slice has a length and capacity of 0 and has no underlying array. https://tour.golang.org/moretypes/12

You return nil, err here:

// in LoadProducts
if err != nil {
    return nil, err
}

but then do

products, _ := d.scrapperService.LoadProducts(702, 1, token)
log.Printf("products count -> %d", len(products)) // gives me 0 <---

which should be

products, err := d.scrapperService.LoadProducts(702, 1, token)
if err != nil {
    panic(err) // dont actually panic, but figure out what went wrong
}
log.Printf("products count -> %d", len(products)) // gives me 0 <---