Błąd: „Obiekt DOMDocument powinien zostać utworzony.” Podczas dodawania / edycji atrybutów produktu

Ilekroć edytuję lub dodam atrybut produktu, pojawia się błąd z nagłówkiem

„Wystąpił błąd podczas przetwarzania Twojego żądania”

i ciało mówi

"Object DOMDocument should be created."

The error log reads :
" a:4:{i:0;s:37:"Object DOMDocument should be created.";i:1;s:10125:"#0 /home/puffpackage/public_html/vendor/magento/framework/View/Element/UiComponent/Config/Reader.php(95): Magento\Framework\View\Element\UiComponent\Config\DomMerger->getDom()
#1 /home/puffpackage/public_html/vendor/magento/module-ui/Model/Manager.php(261): Magento\Framework\View\Element\UiComponent\Config\Reader->read()
#2 /home/puffpackage/public_html/vendor/magento/module-ui/Model/Manager.php(169): Magento\Ui\Model\Manager->prepare('form_schedule_b...')
#3 /home/puffpackage/public_html/vendor/magento/framework/View/Element/UiComponentFactory.php(139): Magento\Ui\Model\Manager->prepareData('form_schedule_b...')
#4 /home/puffpackage/public_html/vendor/magento/framework/View/Layout/Generator/UiComponent.php(125): Magento\Framework\View\Element\UiComponentFactory->create('form_schedule_b...', NULL, Array)
#5 /home/puffpackage/public_html/vendor/magento/framework/View/Layout/Generator/UiComponent.php(93): Magento\Framework\View\Layout\Generator\UiComponent->generateComponent(Object(Magento\Framework\View\Layout\Data\Structure), 'form_schedule_b...', Array, Object(Magento\Framework\View\Layout\Interceptor))
#6 /home/puffpackage/public_html/vendor/magento/framework/View/Layout/GeneratorPool.php(86): Magento\Framework\View\Layout\Generator\UiComponent->process(Object(Magento\Framework\View\Layout\Reader\Context), Object(Magento\Framework\View\Layout\Generator\Context))
#7 /home/puffpackage/public_html/vendor/magento/framework/View/Layout.php(327): Magento\Framework\View\Layout\GeneratorPool->process(Object(Magento\Framework\View\Layout\Reader\Context), Object(Magento\Framework\View\Layout\Generator\Context))
#8 /home/puffpackage/public_html/var/generation/Magento/Framework/View/Layout/Interceptor.php(89): Magento\Framework\View\Layout->generateElements()
#9 /home/puffpackage/public_html/vendor/magento/framework/View/Layout/Builder.php(129): Magento\Framework\View\Layout\Interceptor->generateElements()
#10 /home/puffpackage/public_html/vendor/magento/framework/View/Page/Builder.php(55): Magento\Framework\View\Layout\Builder->generateLayoutBlocks()
#11 /home/puffpackage/public_html/vendor/magento/framework/View/Layout/Builder.php(65): Magento\Framework\View\Page\Builder->generateLayoutBlocks()
#12 /home/puffpackage/public_html/vendor/magento/framework/View/Page/Config.php(166): Magento\Framework\View\Layout\Builder->build()
#13 /home/puffpackage/public_html/vendor/magento/framework/View/Page/Config.php(475): Magento\Framework\View\Page\Config->build()
#14 /home/puffpackage/public_html/vendor/magento/framework/View/Page/Config.php(433): Magento\Framework\View\Page\Config->getElementAttribute('body', 'class')
#15 /home/puffpackage/public_html/vendor/magento/module-catalog/Controller/Adminhtml/Product/Attribute.php(90): Magento\Framework\View\Page\Config->addBodyClass('attribute-popup')
#16 /home/puffpackage/public_html/vendor/magento/module-catalog/Controller/Adminhtml/Product/Attribute/Edit.php(55): Magento\Catalog\Controller\Adminhtml\Product\Attribute->createActionPage(Object(Magento\Framework\Phrase))
#17 /home/puffpackage/public_html/var/generation/Magento/Catalog/Controller/Adminhtml/Product/Attribute/Edit/Interceptor.php(25): Magento\Catalog\Controller\Adminhtml\Product\Attribute\Edit->execute()
#18 /home/puffpackage/public_html/vendor/magento/framework/App/Action/Action.php(102): Magento\Catalog\Controller\Adminhtml\Product\Attribute\Edit\Interceptor->execute()
#19 /home/puffpackage/public_html/vendor/magento/module-backend/App/AbstractAction.php(226): Magento\Framework\App\Action\Action->dispatch(Object(Magento\Framework\App\Request\Http))
#20 /home/puffpackage/public_html/vendor/magento/module-catalog/Controller/Adminhtml/Product/Attribute.php(72): Magento\Backend\App\AbstractAction->dispatch(Object(Magento\Framework\App\Request\Http))
#21 [internal function]: Magento\Catalog\Controller\Adminhtml\Product\Attribute->dispatch(Object(Magento\Framework\App\Request\Http))
#22 /home/puffpackage/public_html/vendor/magento/framework/Interception/Interceptor.php(74): call_user_func_array(Array, Array)
#23 /home/puffpackage/public_html/vendor/magento/framework/Interception/Chain/Chain.php(70): Magento\Catalog\Controller\Adminhtml\Product\Attribute\Edit\Interceptor->___callParent('dispatch', Array)
#24 /home/puffpackage/public_html/vendor/magento/framework/Interception/Chain/Chain.php(63): Magento\Framework\Interception\Chain\Chain->invokeNext('Magento\Catalog...', 'dispatch', Object(Magento\Catalog\Controller\Adminhtml\Product\Attribute\Edit\Interceptor), Array, 'adminAuthentica...')
#25 /home/puffpackage/public_html/vendor/magento/module-backend/App/Action/Plugin/Authentication.php(143): Magento\Framework\Interception\Chain\Chain->Magento\Framework\Interception\Chain\{closure}(Object(Magento\Framework\App\Request\Http))
#26 [internal function]: Magento\Backend\App\Action\Plugin\Authentication->aroundDispatch(Object(Magento\Catalog\Controller\Adminhtml\Product\Attribute\Edit\Interceptor), Object(Closure), Object(Magento\Framework\App\Request\Http))
#27 /home/puffpackage/public_html/vendor/magento/framework/Interception/Chain/Chain.php(68): call_user_func_array(Array, Array)
#28 /home/puffpackage/public_html/vendor/magento/framework/Interception/Chain/Chain.php(63): Magento\Framework\Interception\Chain\Chain->invokeNext('Magento\Catalog...', 'dispatch', Object(Magento\Catalog\Controller\Adminhtml\Product\Attribute\Edit\Interceptor), Array, 'designLoader')
#29 /home/puffpackage/public_html/vendor/magento/framework/App/Action/Plugin/Design.php(39): Magento\Framework\Interception\Chain\Chain->Magento\Framework\Interception\Chain\{closure}(Object(Magento\Framework\App\Request\Http))
#30 [internal function]: Magento\Framework\App\Action\Plugin\Design->aroundDispatch(Object(Magento\Catalog\Controller\Adminhtml\Product\Attribute\Edit\Interceptor), Object(Closure), Object(Magento\Framework\App\Request\Http))
#31 /home/puffpackage/public_html/vendor/magento/framework/Interception/Chain/Chain.php(68): call_user_func_array(Array, Array)
#32 /home/puffpackage/public_html/vendor/magento/framework/Interception/Interceptor.php(136): Magento\Framework\Interception\Chain\Chain->invokeNext('Magento\Catalog...', 'dispatch', Object(Magento\Catalog\Controller\Adminhtml\Product\Attribute\Edit\Interceptor), Array, 'adminMassaction...')
#33 /home/puffpackage/public_html/vendor/magento/module-backend/App/Action/Plugin/MassactionKey.php(33): Magento\Catalog\Controller\Adminhtml\Product\Attribute\Edit\Interceptor->Magento\Framework\Interception\{closure}(Object(Magento\Framework\App\Request\Http))
#34 [internal function]: Magento\Backend\App\Action\Plugin\MassactionKey->aroundDispatch(Object(Magento\Catalog\Controller\Adminhtml\Product\Attribute\Edit\Interceptor), Object(Closure), Object(Magento\Framework\App\Request\Http))
#35 /home/puffpackage/public_html/vendor/magento/framework/Interception/Interceptor.php(141): call_user_func_array(Array, Array)
#36 /home/puffpackage/public_html/var/generation/Magento/Catalog/Controller/Adminhtml/Product/Attribute/Edit/Interceptor.php(40): Magento\Catalog\Controller\Adminhtml\Product\Attribute\Edit\Interceptor->___callPlugins('dispatch', Array, Array)
#37 /home/puffpackage/public_html/vendor/magento/framework/App/FrontController.php(55): Magento\Catalog\Controller\Adminhtml\Product\Attribute\Edit\Interceptor->dispatch(Object(Magento\Framework\App\Request\Http))
#38 [internal function]: Magento\Framework\App\FrontController->dispatch(Object(Magento\Framework\App\Request\Http))
#39 /home/puffpackage/public_html/vendor/magento/framework/Interception/Interceptor.php(74): call_user_func_array(Array, Array)
#40 /home/puffpackage/public_html/vendor/magento/framework/Interception/Chain/Chain.php(70): Magento\Framework\App\FrontController\Interceptor->___callParent('dispatch', Array)
#41 /home/puffpackage/public_html/vendor/magento/framework/Interception/Chain/Chain.php(63): Magento\Framework\Interception\Chain\Chain->invokeNext('Magento\Framewo...', 'dispatch', Object(Magento\Framework\App\FrontController\Interceptor), Array, 'install')
#42 /home/puffpackage/public_html/vendor/magento/framework/Module/Plugin/DbStatusValidator.php(69): Magento\Framework\Interception\Chain\Chain->Magento\Framework\Interception\Chain\{closure}(Object(Magento\Framework\App\Request\Http))
#43 [internal function]: Magento\Framework\Module\Plugin\DbStatusValidator->aroundDispatch(Object(Magento\Framework\App\FrontController\Interceptor), Object(Closure), Object(Magento\Framework\App\Request\Http))
#44 /home/puffpackage/public_html/vendor/magento/framework/Interception/Chain/Chain.php(68): call_user_func_array(Array, Array)
#45 /home/puffpackage/public_html/vendor/magento/framework/Interception/Interceptor.php(136): Magento\Framework\Interception\Chain\Chain->invokeNext('Magento\Framewo...', 'dispatch', Object(Magento\Framework\App\FrontController\Interceptor), Array, 'storeCookieVali...')
#46 /home/puffpackage/public_html/vendor/magento/module-store/Model/Plugin/StoreCookie.php(78): Magento\Framework\App\FrontController\Interceptor->Magento\Framework\Interception\{closure}(Object(Magento\Framework\App\Request\Http))
#47 [internal function]: Magento\Store\Model\Plugin\StoreCookie->aroundDispatch(Object(Magento\Framework\App\FrontController\Interceptor), Object(Closure), Object(Magento\Framework\App\Request\Http))
#48 /home/puffpackage/public_html/vendor/magento/framework/Interception/Interceptor.php(141): call_user_func_array(Array, Array)
#49 /home/puffpackage/public_html/var/generation/Magento/Framework/App/FrontController/Interceptor.php(26): Magento\Framework\App\FrontController\Interceptor->___callPlugins('dispatch', Array, Array)
#50 /home/puffpackage/public_html/vendor/magento/framework/App/Http.php(115): Magento\Framework\App\FrontController\Interceptor->dispatch(Object(Magento\Framework\App\Request\Http))
#51 /home/puffpackage/public_html/vendor/magento/framework/App/Bootstrap.php(258): Magento\Framework\App\Http->launch()
#52 /home/puffpackage/public_html/index.php(39): Magento\Framework\App\Bootstrap->run(Object(Magento\Framework\App\Http))
#53 {main}";s:3:"url";s:244:"/puffmin/catalog/product_attribute/new/store/0/product_tab/variations/popup/1/key/5c2a345ed1b7894fdb9bca01f9daba0c242a4451e6b492633a2d909675076f05/?attribute%5Bis_global%5D=1&attribute%5Bfrontend_input%5D=select&set=4&attribute[frontend_label]=";s:11:"script_name";s:10:"/index.php";} "

Looks like var/generation is not writable. Make sure to set proper file system ownership and permissions: var, app/etc and pub/static should be writable by web server.

Another possible reason for the Object DOMDocument should be created. error is the unaccessible ui_component/your_listing.xml file under the view/adminhtml/ folder when you want to create an Adminhtml Grid and you declare it under the view/adminhtml/layout/your_handle_index.xml as this:

<body>
    <referenceContainer name="content">
        <uiComponent name="your_listing"/>
    </referenceContainer>
</body>

Another possible reason for this error is if your class folders don't have proper capitalization (i.e. are lowercase).

var/log/system.log:

[2016-02-26 21:19:51] main.CRITICAL: Class Example\Myclass\Block\ShopCategory does not exist [] []
[2016-02-26 21:19:51] main.CRITICAL: Invalid block type: Example\Myclass\Block\ShopCategory [] []

For example, if the namespace folder is "example" rather than "Example" it will work just fine on Windows and most Mac installations, but will fail with the "Object DOMDocument should be created." error on Linux, as Linux uses a case-sensitive filesystem.

Recently during a module development I got the same kind of error. In my case I found out the real error which was:

Circular dependency: Vendor\Module\Helper\Data depends on Vendor\Module\Helper\Bot and vice versa.

I removed this dependency from the __construct method of my helpers (refactored them using one parent class) and error is gone. So I'll recommend you to check circular dependencies in your code.

Another kind of error: Fatal Error during render the component, caused by call to the not existing class from 3rd party module.

As I understand this type of error is thrown when the Fatal Error occurs during render of the component and has nothing common with an Object DOM Document.

Well if you have migrated your data from Magento 1 to Magento 2, and if you are getting this error on a specific page, then follow below steps:

If you are getting this error in specific product view page, Category page or any cms page then goto that product/category or CMS page edit section and goto Design section and within layout update XML if any block is added then comment that XML code or remove it and clear your cache and check on the frontend.

I have come across this also.. checking var/log/system.log shows open_basedir restriction in effect. File(/etc/pki/tls/certs)

removing the open_basedir restriction fixed the problem