read error on connection

#0 /var/www/vhosts/kef.com/httpdocs/app/code/community/Cm/RedisSession/Model/Session.php(203): Credis_Client->__call('hIncrBy', Array)
#1 /var/www/vhosts/kef.com/httpdocs/app/code/community/Cm/RedisSession/Model/Session.php(203): Credis_Client->hIncrBy('sess_pmodja1r6t...', 'lock', 1)
#2 [internal function]: Cm_RedisSession_Model_Session->read('pmodja1r6tuchr1...')
#3 /var/www/vhosts/kef.com/httpdocs/app/code/core/Mage/Core/Model/Session/Abstract/Varien.php(133): session_start()
#4 /var/www/vhosts/kef.com/httpdocs/app/code/core/Mage/Core/Model/Session/Abstract/Varien.php(222): Mage_Core_Model_Session_Abstract_Varien->start('frontend')
#5 /var/www/vhosts/kef.com/httpdocs/app/code/core/Mage/Core/Model/Session/Abstract.php(84): Mage_Core_Model_Session_Abstract_Varien->init('core', 'frontend')
#6 /var/www/vhosts/kef.com/httpdocs/app/code/core/Mage/Core/Model/Session.php(42): Mage_Core_Model_Session_Abstract->init('core', 'frontend')
#7 /var/www/vhosts/kef.com/httpdocs/app/code/core/Mage/Core/Model/Config.php(1354): Mage_Core_Model_Session->__construct(Array)
#8 /var/www/vhosts/kef.com/httpdocs/app/Mage.php(463): Mage_Core_Model_Config->getModelInstance('core/session', Array)
#9 /var/www/vhosts/kef.com/httpdocs/app/Mage.php(477): Mage::getModel('core/session', Array)
#10 /var/www/vhosts/kef.com/httpdocs/app/code/core/Mage/Core/Controller/Varien/Action.php(493): Mage::getSingleton('core/session', Array)
#11 /var/www/vhosts/kef.com/httpdocs/app/code/core/Mage/Core/Controller/Front/Action.php(64): Mage_Core_Controller_Varien_Action->preDispatch()
#12 /var/www/vhosts/kef.com/httpdocs/app/code/core/Mage/Core/Controller/Varien/Action.php(407): Mage_Core_Controller_Front_Action->preDispatch()
#13 /var/www/vhosts/kef.com/httpdocs/app/code/core/Mage/Core/Controller/Varien/Router/Standard.php(254): Mage_Core_Controller_Varien_Action->dispatch('process')
#14 /var/www/vhosts/kef.com/httpdocs/app/code/core/Mage/Core/Controller/Varien/Front.php(172): Mage_Core_Controller_Varien_Router_Standard->match(Object(Mage_Core_Controller_Request_Http))
#15 /var/www/vhosts/kef.com/httpdocs/app/code/core/Mage/Core/Model/App.php(354): Mage_Core_Controller_Varien_Front->dispatch()
#16 /var/www/vhosts/kef.com/httpdocs/app/Mage.php(684): Mage_Core_Model_App->run(Array)
#17 /var/www/vhosts/kef.com/httpdocs/index.php(154): Mage::run('base', 'website')
#18 {main}