I have created one extension it is not working in my custom magento application(2.2.4) but it is working fine in default magento2.2.4.
I am getting error because of below code defaul.xml code:
<head> <block class="HK\Hplus\Block\CheckIframe" name="hplus_checkiframe" template="HK_Hplus::checkiframe.phtml"/> </head>
Exception #0 (Magento\Framework\Config\Dom\ValidationException): Element 'block': This element is not expected. Expected is one of ( title, css, link, meta, script, remove, attribute ). Line: 715
When i run my page it is throwing above error I have disabled all third party extension still getting this issue. Same extension working fine in native magento.