WCF::handleException() Unhandled exception: Call to a member function canEnter() on null

#0 /var/www/vhosts/nexgam.de/httpdocs/forum/wcf/lib/page/TodaysPostsListPage.class.php(85): wbb\data\post\Post->canRead()
#1 /var/www/vhosts/nexgam.de/httpdocs/forum/wcf/lib/page/AbstractPage.class.php(273): wcf\page\TodaysPostsListPage->readData()
#2 /var/www/vhosts/nexgam.de/httpdocs/forum/wcf/lib/page/AbstractPage.class.php(100): wcf\page\AbstractPage->show()
#3 /var/www/vhosts/nexgam.de/httpdocs/forum/wcf/lib/system/request/Request.class.php(58): wcf\page\AbstractPage->__run()
#4 /var/www/vhosts/nexgam.de/httpdocs/forum/wcf/lib/system/request/RequestHandler.class.php(139): wcf\system\request\Request->execute()
#5 /var/www/vhosts/nexgam.de/httpdocs/forum/index.php(10): wcf\system\request\RequestHandler->handle('wbb')
#6 {main}