RuntimeException: 'Headers already send (output started at /var/www/html/libraries/joomlatools/library/controller/request/request.php:125' thrown in /var/www/html/libraries/joomlatools/library/dispatcher/response/transport/http.php on line 56

while handling exception

Exception: 'Serialization of 'Closure' is not allowed' thrown in /var/www/html/libraries/src/Cache/Controller/CallbackController.php on line 227

Stacktrace

#0 /var/www/html/libraries/src/Cache/Controller/CallbackController.php(227): serialize()
#1 /var/www/html/libraries/src/Cache/Controller/CallbackController.php(91): Joomla\CMS\Cache\Controller\CallbackController->_makeId()
#2 /var/www/html/libraries/src/Cache/Controller/CallbackController.php(45): Joomla\CMS\Cache\Controller\CallbackController->get()
#3 /var/www/html/components/com_k2/views/itemlist/view.html.php(678): Joomla\CMS\Cache\Controller\CallbackController->call()
#4 /var/www/html/libraries/src/MVC/Controller/BaseController.php(664): K2ViewItemlist->display()
#5 /var/www/html/components/com_k2/controllers/controller.php(19): Joomla\CMS\MVC\Controller\BaseController->display()
#6 /var/www/html/components/com_k2/controllers/itemlist.php(49): K2Controller->display()
#7 /var/www/html/libraries/src/MVC/Controller/BaseController.php(702): K2ControllerItemlist->display()
#8 /var/www/html/components/com_k2/k2.php(64): Joomla\CMS\MVC\Controller\BaseController->execute()
#9 /var/www/html/libraries/src/Component/ComponentHelper.php(402): require_once('/var/www/html/c...')
#10 /var/www/html/libraries/src/Component/ComponentHelper.php(377): Joomla\CMS\Component\ComponentHelper::executeComponent()
#11 /var/www/html/libraries/src/Application/SiteApplication.php(194): Joomla\CMS\Component\ComponentHelper::renderComponent()
#12 /var/www/html/libraries/src/Application/SiteApplication.php(233): Joomla\CMS\Application\SiteApplication->dispatch()
#13 /var/www/html/libraries/src/Application/CMSApplication.php(225): Joomla\CMS\Application\SiteApplication->doExecute()
#14 /var/www/html/index.php(49): Joomla\CMS\Application\CMSApplication->execute()
#15 {main}