[Error] 
Failed to open session: user (path: /tmp/php_sessions/ext_www/s2) (0)
/home/bitrix/www/bitrix/modules/security/classes/general/session.php:55
#0: session_regenerate_id()
	/home/bitrix/www/bitrix/modules/security/classes/general/session.php:55
#1: CSecuritySession::UpdateSessID()
	/home/bitrix/www/bitrix/modules/main/classes/general/module.php:465
#2: ExecuteModuleEventEx(array)
	/home/bitrix/www/bitrix/modules/main/include.php:291
#3: require_once(string)
	/home/bitrix/www/bitrix/modules/main/include/prolog_before.php:14
#4: require_once(string)
	/home/bitrix/www/bitrix/modules/main/include/prolog.php:10
#5: require_once(string)
	/home/bitrix/www/bitrix/header.php:1
#6: require(string)
	/home/bitrix/ext_www/s2/index.php:2
#7: include_once(string)
	/home/bitrix/www/bitrix/modules/main/include/urlrewrite.php:159
#8: include_once(string)
	/home/bitrix/www/bitrix/urlrewrite.php:2