Why is the variant picker not showing on my product page?

Variant_picker isn’t displayed on product page, which was displayed before.

The code of product.json is below.

Please kindly advise.

{
  "sections": {
    "main": {
      "type": "main-product",
      "blocks": {
        "title": {
          "type": "title",
          "settings": {
          }
        },
        "price": {
          "type": "price",
          "settings": {
          }
        },
        "variant_picker": {
          "type": "variant_picker",
          "settings": {
            "show_variant_labels": true,
            "show_quantities": "no"
          }
        },
        "buy_buttons": {
          "type": "buy_buttons",
          "settings": {
            "show_dynamic_checkout": false,
            "show_quantity_selector": true
          }
        },
        "77c69a80-b603-490d-9c25-babef6998d45": {
          "type": "shopify:\/\/apps\/cc-delivery-date-time\/blocks\/cart-dellivery-1988\/778b3c9d-6aee-4460-9828-0c408353c91b",
          "settings": {
            "css": ".cc-calendar-overall{}"
          }
        },
        "description": {
          "type": "description",
          "settings": {
            "product_description_truncated": "truncated--disabled"
          }
        },
        "share": {
          "type": "share",
          "settings": {
          }
        },
        "d664130e-2dfe-48da-81f0-2df8b3d87ea8": {
          "type": "collapsible_tab",
          "settings": {
            "heading": "商品詳細",
            "content": "<p>{{ product.metafields.my_fields._eating | metafield_tag }}<br\/>{{ product.metafields.my_fields._size | metafield_tag }}<br\/>{{ product.metafields.my_fields._eatdate | metafield_tag }}<br\/>{{ product.metafields.my_fields._material | metafield_tag }}<br\/>{{ product.metafields.my_fields._allergy_disc | metafield_tag }}<br\/>{{ product.metafields.my_fields._delivalydate | metafield_tag }}<br\/>{{ product.metafields.my_fields._delivalyfee | metafield_tag }}<br\/>{{ product.metafields.my_fields._delivaly_area | metafield_tag }}<br\/>{{ product.metafields.my_fields._delivaly_Method | metafield_tag }}<br\/>{{ product.metafields.my_fields._delivaly_Trader | metafield_tag }}<br\/>{{ product.metafields.my_fields._gift_taiou | metafield_tag }}<\/p>",
            "page": ""
          }
        }
      },
      "block_order": [
        "title",
        "price",
        "buy_buttons",
        "variant_picker",
        "description",
        "share",
        "d664130e-2dfe-48da-81f0-2df8b3d87ea8"
      ],
      "settings": {
        "gallery_style": "slider",
        "gallery_slider_style": true,
        "gallery_pagination": "dots",
        "gallery_gutter": false,
        "enable_zoom": true,
        "enable_video_looping": false
      }
    },
    "163783371389b41e4b": {
      "type": "heading",
      "settings": {
        "title": "Store"
      }
    },
    "16378336541a9c4fa3": {
      "type": "rich-text",
      "blocks": {
        "1637833654bf7943eb-0": {
          "type": "heading",
          "settings": {
            "heading": "<p>{{ product.vendor }}<\/p>",
            "heading_size": "regular"
          }
        },
        "1637833654bf7943eb-1": {
          "type": "text",
          "settings": {
            "text": "<p>{{ product.metafields.my_fields._storeDescription | metafield_tag }}<\/p><p>販売者:{{ product.metafields.my_fields._Seller | metafield_tag }}<br\/>住所:{{ product.metafields.my_fields._storeAddress.value }}<\/p><p><\/p>"
          }
        }
      },
      "block_order": [
        "1637833654bf7943eb-0",
        "1637833654bf7943eb-1"
      ],
      "settings": {
        "text_alignment": "left",
        "image": "{{ product.metafields.my_fields._store_img.value }}",
        "image_position": "align-right",
        "image_height": "50vh",
        "color_text": "rgba(0,0,0,0)",
        "color_bg": "rgba(0,0,0,0)"
      }
    },
    "product-recommendations": {
      "type": "product-recommendations",
      "settings": {
        "heading": "Recommend"
      }
    }
  },
  "order": [
    "main",
    "163783371389b41e4b",
    "16378336541a9c4fa3",
    "product-recommendations"
  ]
}