Magento2 Install Schema cant add FK

I am trying to add 2 FK in install schema but it returned cant add constraint. May I know why?

<?php

namespace MyModuleConnectProductSetup;

use MagentoFrameworkSetupInstallSchemaInterface;
use MagentoFrameworkSetupModuleContextInterface;
use MagentoFrameworkSetupSchemaSetupInterface;
use MagentoFrameworkDBDdlTable;
use phpDocumentorReflectionType;

class InstallSchema implements InstallSchemaInterface{
public function install(SchemaSetupInterface $setup, ModuleContextInterface $context)
{
    $setup->startSetup();

    $table = $setup->getConnection()->newTable(
       'product_seller'
    )->addColumn(
        'id',
        Table::TYPE_INTEGER,
        null,
        ['identity' => true, 'nullable' => false, 'primary' => true]
    )->addColumn(
            'product_id',
            Table::TYPE_INTEGER,
            null,
            ['nullable' => false],
            'product_id'
        )->addForeignKey(
        $setup->getFkName(
                'product_seller',
                'product_id',
                'catalog_product_entity',
                'entity_id'
            ),
            'product_id',
        $setup->getTable('catalog_product_entity'),
            'entity_id',
            Table::ACTION_CASCADE
    )->addColumn(
        'seller_id',
        Table::TYPE_TEXT,
        255,
        ['nullable' => false],
        'seller_id'
        )->addForeignKey(
            $setup->getFkName(
                'product_seller',
                'seller_id',
                'newentity_seller',
                'id'
            ),
        'seller_id',
        $setup->getTable('newentity_seller'),
        'seller_id',
        Table::ACTION_CASCADE
    )->setComment("News Table");



    $setup->getConnection()->createTable($table);

    $setup->endSetup();
}

}