[Bitrix\Main\DB\SqlQueryException] 
Mysql query error: (2006) MySQL server has gone away (400)
delete from b_sec_session where TIMESTAMP_X < DATE_ADD(NOW(), INTERVAL -1440 SECOND)
/home/bitrix/www/bitrix/modules/main/lib/db/mysqliconnection.php:137
#0: Bitrix\Main\DB\MysqliConnection->queryInternal(string, array, NULL)
	/home/bitrix/www/bitrix/modules/main/lib/db/connection.php:330
#1: Bitrix\Main\DB\Connection->query(string, NULL)
	/home/bitrix/www/bitrix/modules/main/lib/db/connection.php:379
#2: Bitrix\Main\DB\Connection->queryExecute(string)
	/home/bitrix/www/bitrix/modules/security/lib/session.php:248
#3: Bitrix\Security\SessionTable::deleteOlderThan(integer)
	/home/bitrix/www/bitrix/modules/security/classes/general/session_db.php:136
#4: CSecuritySessionDB::gc(integer)
	/home/bitrix/www/bitrix/modules/security/classes/general/session_handler.php:38
#5: CSecuritySessionHandler->gc(integer)
	
#6: session_start()
	/home/bitrix/www/bitrix/modules/main/include.php:288
#7: require_once(string)
	/home/bitrix/www/bitrix/modules/main/include/prolog_before.php:14
#8: require_once(string)
	/home/bitrix/www/bitrix/modules/main/include/prolog.php:10
#9: require_once(string)
	/home/bitrix/www/bitrix/header.php:1
#10: require(string)
	/home/bitrix/ext_www/s2/index.php:2
#11: include_once(string)
	/home/bitrix/www/bitrix/modules/main/include/urlrewrite.php:159
#12: include_once(string)
	/home/bitrix/www/bitrix/urlrewrite.php:2