Error "Class GroupGridDataProvider does not exist"

I installed the module and am able to login to backend of store, but when I click the “Manage Menu” link to edit the menu, I get the following error: 

1 exception(s):
Exception #0 (ReflectionException): Class GroupGridDataProvider does not exist

Exception #0 (ReflectionException): Class GroupGridDataProvider does not exist
#0 /var/www/store.shadeware.com/public_html/vendor/magento/framework/Code/Reader/ClassReader.php(19): ReflectionClass->__construct('GroupGridDataPr...')
#1 /var/www/store.shadeware.com/public_html/vendor/magento/framework/ObjectManager/Definition/Runtime.php(44): Magento\Framework\Code\Reader\ClassReader->getConstructor('GroupGridDataPr...')
#2 /var/www/store.shadeware.com/public_html/vendor/magento/framework/ObjectManager/Factory/Compiled.php(100): Magento\Framework\ObjectManager\Definition\Runtime->getParameters('GroupGridDataPr...')
#3 /var/www/store.shadeware.com/public_html/vendor/magento/framework/ObjectManager/ObjectManager.php(56): Magento\Framework\ObjectManager\Factory\Compiled->create('GroupGridDataPr...', Array)
#4 /var/www/store.shadeware.com/public_html/vendor/magento/framework/View/Element/UiComponent/Argument/Interpreter/ConfigurableObject.php(60): Magento\Framework\ObjectManager\ObjectManager->create('GroupGridDataPr...', Array)
#5 /var/www/store.shadeware.com/public_html/generated/code/Magento/Framework/Data/Argument/InterpreterInterface/Proxy.php(95): Magento\Framework\View\Element\UiComponent\Argument\Interpreter\ConfigurableObject->evaluate(Array)
#6 /var/www/store.shadeware.com/public_html/vendor/magento/framework/Data/Argument/Interpreter/Composite.php(61): Magento\Framework\Data\Argument\InterpreterInterface\Proxy->evaluate(Array)
#7 /var/www/store.shadeware.com/public_html/vendor/magento/module-ui/Config/Data.php(164): Magento\Framework\Data\Argument\Interpreter\Composite->evaluate(Array)
#8 /var/www/store.shadeware.com/public_html/vendor/magento/module-ui/Config/Data.php(167): Magento\Ui\Config\Data->evaluateComponentArguments(Array)
#9 /var/www/store.shadeware.com/public_html/vendor/magento/module-ui/Config/Data.php(111): Magento\Ui\Config\Data->evaluateComponentArguments(Array)
#10 /var/www/store.shadeware.com/public_html/vendor/magento/module-ui/Config/Data.php(136): Magento\Ui\Config\Data->initData()
#11 /var/www/store.shadeware.com/public_html/vendor/magento/framework/View/Layout/Reader/UiComponent.php(100): Magento\Ui\Config\Data->get('ubmegamenu_grou...')
#12 /var/www/store.shadeware.com/public_html/vendor/magento/framework/View/Layout/ReaderPool.php(105): Magento\Framework\View\Layout\Reader\UiComponent->interpret(Object(Magento\Framework\View\Layout\Reader\Context), Object(Magento\Framework\View\Layout\Element), Object(Magento\Framework\View\Layout\Element))
#13 /var/www/store.shadeware.com/public_html/vendor/magento/framework/View/Layout/Reader/Container.php(89): Magento\Framework\View\Layout\ReaderPool->interpret(Object(Magento\Framework\View\Layout\Reader\Context), Object(Magento\Framework\View\Layout\Element))
#14 /var/www/store.shadeware.com/public_html/vendor/magento/framework/View/Layout/ReaderPool.php(105): Magento\Framework\View\Layout\Reader\Container->interpret(Object(Magento\Framework\View\Layout\Reader\Context), Object(Magento\Framework\View\Layout\Element), Object(Magento\Framework\View\Layout\Element))
#15 /var/www/store.shadeware.com/public_html/vendor/magento/framework/View/Page/Config/Reader/Body.php(68): Magento\Framework\View\Layout\ReaderPool->interpret(Object(Magento\Framework\View\Layout\Reader\Context), Object(Magento\Framework\View\Layout\Element))
#16 /var/www/store.shadeware.com/public_html/vendor/magento/framework/View/Layout/ReaderPool.php(105): Magento\Framework\View\Page\Config\Reader\Body->interpret(Object(Magento\Framework\View\Layout\Reader\Context), Object(Magento\Framework\View\Layout\Element), Object(Magento\Framework\View\Layout\Element))
#17 /var/www/store.shadeware.com/public_html/vendor/magento/framework/View/Layout.php(325): Magento\Framework\View\Layout\ReaderPool->interpret(Object(Magento\Framework\View\Layout\Reader\Context), Object(Magento\Framework\View\Layout\Element))
#18 /var/www/store.shadeware.com/public_html/vendor/magento/framework/View/Layout/Builder.php(129): Magento\Framework\View\Layout->generateElements()
#19 /var/www/store.shadeware.com/public_html/vendor/magento/framework/View/Page/Builder.php(55): Magento\Framework\View\Layout\Builder->generateLayoutBlocks()
#20 /var/www/store.shadeware.com/public_html/vendor/magento/framework/View/Layout/Builder.php(65): Magento\Framework\View\Page\Builder->generateLayoutBlocks()
#21 /var/www/store.shadeware.com/public_html/vendor/magento/framework/View/Layout.php(253): Magento\Framework\View\Layout\Builder->build()
#22 /var/www/store.shadeware.com/public_html/vendor/magento/framework/View/Layout.php(875): Magento\Framework\View\Layout->build()
#23 /var/www/store.shadeware.com/public_html/vendor/magento/module-backend/Model/View/Result/Page.php(26): Magento\Framework\View\Layout->getBlock('menu')
#24 /var/www/store.shadeware.com/public_html/app/code/Ubertheme/UbMegaMenu/Controller/Adminhtml/Group/Index.php(54): Magento\Backend\Model\View\Result\Page->setActiveMenu('Ubertheme_UbMeg...')
#25 /var/www/store.shadeware.com/public_html/vendor/magento/framework/App/Action/Action.php(107): Ubertheme\UbMegaMenu\Controller\Adminhtml\Group\Index->execute()
#26 /var/www/store.shadeware.com/public_html/vendor/magento/module-backend/App/AbstractAction.php(235): Magento\Framework\App\Action\Action->dispatch(Object(Magento\Framework\App\Request\Http))
#27 /var/www/store.shadeware.com/public_html/vendor/magento/framework/Interception/Interceptor.php(58): Magento\Backend\App\AbstractAction->dispatch(Object(Magento\Framework\App\Request\Http))
#28 /var/www/store.shadeware.com/public_html/vendor/magento/framework/Interception/Interceptor.php(138): Ubertheme\UbMegaMenu\Controller\Adminhtml\Group\Index\Interceptor->___callParent('dispatch', Array)
#29 /var/www/store.shadeware.com/public_html/vendor/magento/module-backend/App/Action/Plugin/Authentication.php(143): Ubertheme\UbMegaMenu\Controller\Adminhtml\Group\Index\Interceptor->Magento\Framework\Interception\{closure}(Object(Magento\Framework\App\Request\Http))
#30 /var/www/store.shadeware.com/public_html/vendor/magento/framework/Interception/Interceptor.php(135): Magento\Backend\App\Action\Plugin\Authentication->aroundDispatch(Object(Ubertheme\UbMegaMenu\Controller\Adminhtml\Group\Index\Interceptor), Object(Closure), Object(Magento\Framework\App\Request\Http))
#31 /var/www/store.shadeware.com/public_html/app/code/Bss/ForceLogin/Plugin/OtherPage.php(95): Ubertheme\UbMegaMenu\Controller\Adminhtml\Group\Index\Interceptor->Magento\Framework\Interception\{closure}(Object(Magento\Framework\App\Request\Http))
#32 /var/www/store.shadeware.com/public_html/vendor/magento/framework/Interception/Interceptor.php(135): Bss\ForceLogin\Plugin\OtherPage->aroundDispatch(Object(Ubertheme\UbMegaMenu\Controller\Adminhtml\Group\Index\Interceptor), Object(Closure), Object(Magento\Framework\App\Request\Http))
#33 /var/www/store.shadeware.com/public_html/vendor/magento/framework/Interception/Interceptor.php(153): Ubertheme\UbMegaMenu\Controller\Adminhtml\Group\Index\Interceptor->Magento\Framework\Interception\{closure}(Object(Magento\Framework\App\Request\Http))
#34 /var/www/store.shadeware.com/public_html/generated/code/Ubertheme/UbMegaMenu/Controller/Adminhtml/Group/Index/Interceptor.php(26): Ubertheme\UbMegaMenu\Controller\Adminhtml\Group\Index\Interceptor->___callPlugins('dispatch', Array, NULL)
#35 /var/www/store.shadeware.com/public_html/vendor/magento/framework/App/FrontController.php(55): Ubertheme\UbMegaMenu\Controller\Adminhtml\Group\Index\Interceptor->dispatch(Object(Magento\Framework\App\Request\Http))
#36 /var/www/store.shadeware.com/public_html/vendor/magento/framework/Interception/Interceptor.php(58): Magento\Framework\App\FrontController->dispatch(Object(Magento\Framework\App\Request\Http))
#37 /var/www/store.shadeware.com/public_html/vendor/magento/framework/Interception/Interceptor.php(138): Magento\Framework\App\FrontController\Interceptor->___callParent('dispatch', Array)
#38 /var/www/store.shadeware.com/public_html/vendor/magento/framework/Interception/Interceptor.php(153): Magento\Framework\App\FrontController\Interceptor->Magento\Framework\Interception\{closure}(Object(Magento\Framework\App\Request\Http))
#39 /var/www/store.shadeware.com/public_html/generated/code/Magento/Framework/App/FrontController/Interceptor.php(26): Magento\Framework\App\FrontController\Interceptor->___callPlugins('dispatch', Array, Array)
#40 /var/www/store.shadeware.com/public_html/vendor/magento/framework/App/Http.php(135): Magento\Framework\App\FrontController\Interceptor->dispatch(Object(Magento\Framework\App\Request\Http))
#41 /var/www/store.shadeware.com/public_html/vendor/magento/framework/App/Bootstrap.php(257): Magento\Framework\App\Http->launch()
#42 /var/www/store.shadeware.com/public_html/index.php(39): Magento\Framework\App\Bootstrap->run(Object(Magento\Framework\App\Http\Interceptor))
#43 {main}

Please provide any support on how to fix.