[Bitrix\Main\DB\SqlQueryException] 
Mysql query error: (2006) MySQL server has gone away (400)
SELECT * FROM `b_sec_session` LIMIT 0
/home/bitrix/www/bitrix/modules/main/lib/db/mysqliconnection.php:137
#0: Bitrix\Main\DB\MysqliConnection->queryInternal(string)
	/home/bitrix/www/bitrix/modules/main/lib/db/mysqlcommonconnection.php:104
#1: Bitrix\Main\DB\MysqlCommonConnection->getTableFields(string)
	/home/bitrix/www/bitrix/modules/main/lib/db/connection.php:779
#2: Bitrix\Main\DB\Connection->getTableField(string, string)
	/home/bitrix/www/bitrix/modules/main/lib/db/sqlhelper.php:406
#3: Bitrix\Main\DB\SqlHelper->prepareAssignment(string, string, string)
	/home/bitrix/www/bitrix/modules/main/lib/orm/data/datamanager.php:1619
#4: Bitrix\Main\ORM\Data\DataManager::delete(array)
	/home/bitrix/www/bitrix/modules/security/classes/general/session_db.php:100
#5: CSecuritySessionDB::write(string, string)
	/home/bitrix/www/bitrix/modules/security/classes/general/session_handler.php:28
#6: CSecuritySessionHandler->write(string, string)
	
#7: session_regenerate_id()
	/home/bitrix/www/bitrix/modules/security/classes/general/session.php:55
#8: CSecuritySession::UpdateSessID()
	/home/bitrix/www/bitrix/modules/main/classes/general/module.php:465
#9: ExecuteModuleEventEx(array)
	/home/bitrix/www/bitrix/modules/main/include.php:292
#10: require_once(string)
	/home/bitrix/www/bitrix/modules/main/include/prolog_before.php:14
#11: require_once(string)
	/home/bitrix/www/bitrix/modules/main/include/prolog.php:10
#12: require_once(string)
	/home/bitrix/www/bitrix/header.php:1
#13: require(string)
	/home/bitrix/www/catalog/index.php:2
#14: include_once(string)
	/home/bitrix/www/bitrix/modules/main/include/urlrewrite.php:159
#15: include_once(string)
	/home/bitrix/www/bitrix/urlrewrite.php:2