Class Magefan\Blog\Block\Adminhtml\Edit\BackButton does not exist

[r0umi]

configuration :
Magento enterprise 2.2.2
Magefan blog 2.8.6
infrastructure : magento cloud

step to reproduce :
Go to backoffice > content > Blog > Posts and click "add new post"

result :
Something went wrong while saving this post. Class Magefan\Blog\Block\Adminhtml\Edit\BackButton does not exist

expected :
the form to add a new post.

stacktrace :
report.CRITICAL: Exception message: Class Magefan\Blog\Block\Adminhtml\Edit\BackButton does not exist
Trace: #0 /var/www/html/vendor/magento/framework/Code/Reader/ClassReader.php(19): ReflectionClass->__construct('Magefan\Blog\Bl...')
#1 /var/www/html/vendor/magento/framework/ObjectManager/Definition/Runtime.php(44): Magento\Framework\Code\Reader\ClassReader->getConstructor('Magefan\Blog\Bl...')
#2 /var/www/html/vendor/magento/framework/ObjectManager/Factory/Dynamic/Developer.php(48): Magento\Framework\ObjectManager\Definition\Runtime->getParameters('Magefan\Blog\Bl...')
#3 /var/www/html/vendor/magento/framework/ObjectManager/ObjectManager.php(56): Magento\Framework\ObjectManager\Factory\Dynamic\Developer->create('Magefan\Blog\Bl...', Array)
#4 /var/www/html/vendor/magento/framework/View/Element/UiComponent/Control/ButtonProviderFactory.php(39): Magento\Framework\ObjectManager\ObjectManager->create('Magefan\Blog\Bl...', Array)
#5 /var/www/html/vendor/magento/framework/View/Element/UiComponent/Context.php(267): Magento\Framework\View\Element\UiComponent\Control\ButtonProviderFactory->create('Magefan\Blog\Bl...')
#6 /var/www/html/vendor/magento/module-ui/Component/AbstractComponent.php(116): Magento\Framework\View\Element\UiComponent\Context->addButtons(Array, Object(Magento\Ui\Component\Form))
#7 /var/www/html/vendor/magento/framework/View/Layout/Generator/UiComponent.php(159): Magento\Ui\Component\AbstractComponent->prepare()
#8 /var/www/html/vendor/magento/framework/View/Layout/Generator/UiComponent.php(137): Magento\Framework\View\Layout\Generator\UiComponent->prepareComponent(Object(Magento\Ui\Component\Form))
#9 /var/www/html/vendor/magento/framework/View/Layout/Generator/UiComponent.php(97): Magento\Framework\View\Layout\Generator\UiComponent->generateComponent(Object(Magento\Framework\View\Layout\Data\Structure), 'blog_post_form', Array, Object(Magento\Framework\View\Layout\Interceptor))
#10 /var/www/html/vendor/magento/framework/View/Layout/GeneratorPool.php(80): Magento\Framework\View\Layout\Generator\UiComponent->process(Object(Magento\Framework\View\Layout\Reader\Context), Object(Magento\Framework\View\Layout\Generator\Context))
#11 /var/www/html/vendor/magento/framework/View/Layout.php(344): Magento\Framework\View\Layout\GeneratorPool->process(Object(Magento\Framework\View\Layout\Reader\Context), Object(Magento\Framework\View\Layout\Generator\Context))
#12 /var/www/html/generated/code/Magento/Framework/View/Layout/Interceptor.php(89): Magento\Framework\View\Layout->generateElements()
#13 /var/www/html/vendor/magento/framework/View/Layout/Builder.php(129): Magento\Framework\View\Layout\Interceptor->generateElements()
#14 /var/www/html/vendor/magento/framework/View/Page/Builder.php(55): Magento\Framework\View\Layout\Builder->generateLayoutBlocks()
#15 /var/www/html/vendor/magento/framework/View/Layout/Builder.php(65): Magento\Framework\View\Page\Builder->generateLayoutBlocks()
#16 /var/www/html/vendor/magento/framework/View/Page/Config.php(197): Magento\Framework\View\Layout\Builder->build()
#17 /var/www/html/vendor/magento/framework/View/Page/Config.php(207): Magento\Framework\View\Page\Config->build()
#18 /var/www/html/vendor/magento/framework/App/View.php(170): Magento\Framework\View\Page\Config->publicBuild()
#19 /var/www/html/vendor/magento/framework/App/View.php(114): Magento\Framework\App\View->loadLayoutUpdates()
#20 /var/www/html/vendor/magefan/module-community/Controller/Adminhtml/Actions.php(166): Magento\Framework\App\View->loadLayout()
#21 /var/www/html/generated/code/Magefan/Blog/Controller/Adminhtml/Post/Edit/Interceptor.php(37): Magefan\Community\Controller\Adminhtml\Actions->_editAction()
#22 /var/www/html/vendor/magefan/module-community/Controller/Adminhtml/Actions.php(108): Magefan\Blog\Controller\Adminhtml\Post\Edit\Interceptor->_editAction()
#23 /var/www/html/generated/code/Magefan/Blog/Controller/Adminhtml/Post/Edit/Interceptor.php(24): Magefan\Community\Controller\Adminhtml\Actions->execute()
#24 /var/www/html/vendor/magento/framework/App/Action/Action.php(107): Magefan\Blog\Controller\Adminhtml\Post\Edit\Interceptor->execute()
#25 /var/www/html/vendor/magento/module-backend/App/AbstractAction.php(229): Magento\Framework\App\Action\Action->dispatch(Object(Magento\Framework\App\Request\Http))
#26 /var/www/html/vendor/magento/framework/Interception/Interceptor.php(58): Magento\Backend\App\AbstractAction->dispatch(Object(Magento\Framework\App\Request\Http))
#27 /var/www/html/vendor/magento/framework/Interception/Interceptor.php(138): Magefan\Blog\Controller\Adminhtml\Post\Edit\Interceptor->___callParent('dispatch', Array)
#28 /var/www/html/vendor/magento/module-backend/App/Action/Plugin/Authentication.php(143): Magefan\Blog\Controller\Adminhtml\Post\Edit\Interceptor->Magento\Framework\Interception{closure}(Object(Magento\Framework\App\Request\Http))
#29 /var/www/html/vendor/magento/framework/Interception/Interceptor.php(135): Magento\Backend\App\Action\Plugin\Authentication->aroundDispatch(Object(Magefan\Blog\Controller\Adminhtml\Post\Edit\Interceptor), Object(Closure), Object(Magento\Framework\App\Request\Http))
#30 /var/www/html/vendor/magento/framework/Interception/Interceptor.php(153): Magefan\Blog\Controller\Adminhtml\Post\Edit\Interceptor->Magento\Framework\Interception{closure}(Object(Magento\Framework\App\Request\Http))
#31 /var/www/html/generated/code/Magefan/Blog/Controller/Adminhtml/Post/Edit/Interceptor.php(65): Magefan\Blog\Controller\Adminhtml\Post\Edit\Interceptor->___callPlugins('dispatch', Array, NULL)
#32 /var/www/html/vendor/magento/framework/App/FrontController.php(55): Magefan\Blog\Controller\Adminhtml\Post\Edit\Interceptor->dispatch(Object(Magento\Framework\App\Request\Http))
#33 /var/www/html/vendor/magento/framework/Interception/Interceptor.php(58): Magento\Framework\App\FrontController->dispatch(Object(Magento\Framework\App\Request\Http))
#34 /var/www/html/vendor/magento/framework/Interception/Interceptor.php(138): Magento\Framework\App\FrontController\Interceptor->___callParent('dispatch', Array)
#35 /var/www/html/vendor/magento/framework/Interception/Interceptor.php(153): Magento\Framework\App\FrontController\Interceptor->Magento\Framework\Interception{closure}(Object(Magento\Framework\App\Request\Http))
#36 /var/www/html/generated/code/Magento/Framework/App/FrontController/Interceptor.php(26): Magento\Framework\App\FrontController\Interceptor->___callPlugins('dispatch', Array, Array)
#37 /var/www/html/vendor/magento/framework/App/Http.php(135): Magento\Framework\App\FrontController\Interceptor->dispatch(Object(Magento\Framework\App\Request\Http))
#38 /var/www/html/generated/code/Magento/Framework/App/Http/Interceptor.php(24): Magento\Framework\App\Http->launch()
#39 /var/www/html/vendor/magento/framework/App/Bootstrap.php(256): Magento\Framework\App\Http\Interceptor->launch()
#40 /var/www/html/pub/index.php(37): Magento\Framework\App\Bootstrap->run(Object(Magento\Framework\App\Http\Interceptor))
#41 {main}

[magefan]

@r0umi , thank you for your report.
Please make sure that you use the official release of the Magento 2 blog extension by Magefan also the problem can be in some module that extends Magefan blog.

We have checked our code base
https://github.com/magefan/module-blog/search?q=BackButton&unscoped_q=BackButton
and we can find BackButton only in the UI component XML, but it is actually
Magefan\Community\Block\Adminhtml\Edit\BackButton
and not
Magefan\Blog\Block\Adminhtml\Edit\BackButton

So I recommend you to check your code and replace
Magefan\Blog\Block\Adminhtml\Edit\BackButton
with
Magefan\Community\Block\Adminhtml\Edit\BackButton

[r0umi]

Hello,

This issue comes from an override in our code.
Thank you for the reply and sorry for the disruption.

You can close this ticket.
Regards, Romain

[magefan]

Hello @r0umi, thank you for let us know.
Was our Blog extension useful for you? Hope you are happy with it.
Could I ask you please to leave a GitHub star and an honest review about the module on our website?
https://magefan.com/magento2-blog-extension