Display Product image issue in order email magento2

I am trying to show product image in order emails.

for that i overrided below file to my custom theme to implement it.

Magento_Sales/templates/email/items/order/default.phtml

$  _order = $  _item->getOrder(); $  _store = $  _order->getStore(); $  _imageHelper = \Magento\Framework\App\ObjectManager::getInstance()- >get('Magento\Catalog\Helper\Image'); $  _baseImageUrl = $  _store->getBaseUrl(\Magento\Framework\UrlInterface::URL_TYPE_MEDIA).'catalog/product';  $  productRepository = \Magento\Framework\App\ObjectManager::getInstance()->get('Magento\Catalog\Api\ProductRepositoryInterface'); $  productSku = $  block->getSku($  _item); $  productObj = $  productRepository->get($  productSku); $  imageUrl = $  _imageHelper->init($  productObj, 'small_image', ['type'=>'small_image'])->keepAspectRatio(true)->resize('65','65')->getUrl(); 

Then after the line

<p class="product-name"><?= $  block->escapeHtml($  _item->getName()) ?></p> 

I added my code like below.

  <p><img src="<?php echo $  imageUrl; ?>" alt="Product Image"></p>     

This is showing always src as unknown.

But the image is there.

Can anyone help me to resolve this issue?

Thanks