invalid block type

[pavanusn]

while i'm trying to open the admin side grid i'm getting the error as

Invalid block type: YourCompanyName\YourModuleName\Block\Adminhtml\Modelname\Grid
#0 /var/www/html/magento22/vendor/magento/framework/View/Layout/Generator/Block.php(237): Magento\Framework\View\Layout\Generator\Block->getBlockInstance('YourCompanyName...', Array)