Fatal error: Uncaught Error: Call to a member function getStoreIds() on null in /home/thechess/public_html/app/code/Mageplaza/Blog/Block/Adminhtml/Category/Tree.php:178 Stack trace: #0 /home/thechess/public_html/vendor/magento/module-catalog/Block/Adminhtml/Category/Tree.php(301): Mageplaza\Blog\Block\Adminhtml\Category\Tree->_getNodeJson(NULL) #1 /home/thechess/public_html/app/code/Mageplaza/Blog/Block/Adminhtml/Category/Tree.php(140): Magento\Catalog\Block\Adminhtml\Category\Tree->getTree(NULL) #2 /home/thechess/public_html/app/code/Mageplaza/Blog/Block/Category/Widget.php(44): Mageplaza\Blog\Block\Adminhtml\Category\Tree->getTree(NULL, '1') #3 /home/thechess/public_html/app/code/Mageplaza/Blog/view/frontend/templates/category/widget.phtml(22): Mageplaza\Blog\Block\Category\Widget->getTree() #4 /home/thechess/public_html/vendor/magento/framework/View/TemplateEngine/Php.php(59): include('/home/thechess/...') #5 /home/thechess/public_html/vendor/magento/framework/View/Element/Template.php(271): Magento\Framework\View\Temp in /home/thechess/public_html/app/code/Mageplaza/Blog/Block/Adminhtml/Category/Tree.php on line 178