Fatal error: Uncaught exception 'Zend_Session_Exception' with message  'Zend_Session::start() - /var/www/cas-portal/library/Zend/Session.php(Line:480): Error #2 session_start(): Failed to read session data: files (path: /var/lib/php/sessions) Array'

Stack trace:
#0 /var/www/cas-portal/library/Zend/Session/Namespace.php(143): Zend_Session::start(true)
#1 /var/www/cas-portal/library/Zend/Auth/Storage/Session.php(87): Zend_Session_Namespace->__construct('Zend_Auth')
#2 /var/www/cas-portal/application/Bootstrap.php(6): Zend_Auth_Storage_Session->__construct()
#3 /var/www/cas-portal/library/Zend/Application/Bootstrap/BootstrapAbstract.php(667): Bootstrap->_initAuthStorage()
#4 /var/www/cas-portal/library/Zend/Application/Bootstrap/BootstrapAbstract.php(620): Zend_Application_Bootstrap_BootstrapAbstract->_executeResource('authstorage')
#5 /var/www/cas-portal/library/Zend/Application/Bootstrap/BootstrapAbstract.php(584): Zend_Application_Bootstrap_BootstrapAbstract->_bootstrap('authstorage')
#6 /var/www/cas-portal/library/Zend/Application.php(355): Zend_Application_Bootstrap_BootstrapAbstract->bootstrap(NULL)
#7 /var/www/cas-portal/public/index.php(51): Zend_Application->bootstrap()
#8 {main}