How to fix the issue in contao Isotope help class not found?

Please help me how to fix the issue. I am new to contao CMS.

Warning: in_array() expects parameter 2 to be array, null given in system/modules/core/library/Contao/System.php on line 130

#0 [internal function]: __error(2, 'in_array() expe...', '/home/dating/do...', 130, Array)
#1 system/modules/core/library/Contao/System.php(130): in_array('getInstance', NULL)
#2 system/modules/core/library/Contao/System.php(306): Contao\System::importStatic('Isotope\Backend...')
#3 system/modules/core/library/Contao/User.php(227): Contao\System::loadLanguageFile('default')
#4 contao/index.php(53): Contao\User->login()
#5 contao/index.php(129): Index->__construct()
#6 {main}

Fatal error: Class 'Isotope\Backend\ProductType\Help' not found in /home/system/modules/core/library/Contao/System.php on line 130

//Moderation: Moved the thread to the appropriate extension subforum

Hey, you have to set up Isotope properly. There clearly is an issue with the dependencies.
Just go to the extension repository and install Isotope from there. It will automatically grab all the deps for you :)