[Bitrix\Main\DB\SqlQueryException] 
Mysql query error: (2006) MySQL server has gone away (400)
SELECT 
	`security_session`.`SESSION_DATA` AS `SESSION_DATA`
FROM `b_sec_session` `security_session` 

WHERE `security_session`.`SESSION_ID` = 'pE4Btg84T4L4q2kXuFW63I4vkFq2Ug6u'
LIMIT 0, 1

/home/bitrix/shared-student/bitrix/modules/main/lib/db/mysqliconnection.php:137
#0: Bitrix\Main\DB\MysqliConnection->queryInternal(string, array, NULL)
	/home/bitrix/shared-student/bitrix/modules/main/lib/db/connection.php:330
#1: Bitrix\Main\DB\Connection->query(string)
	/home/bitrix/shared-student/bitrix/modules/main/lib/orm/query/query.php:3193
#2: Bitrix\Main\ORM\Query\Query->query(string)
	/home/bitrix/shared-student/bitrix/modules/main/lib/orm/query/query.php:806
#3: Bitrix\Main\ORM\Query\Query->exec()
	/home/bitrix/shared-student/bitrix/modules/main/lib/orm/data/datamanager.php:457
#4: Bitrix\Main\ORM\Data\DataManager::getList(array)
	/home/bitrix/shared-student/bitrix/modules/main/lib/orm/data/datamanager.php:367
#5: Bitrix\Main\ORM\Data\DataManager::getRow(array)
	/home/bitrix/shared-student/bitrix/modules/security/classes/general/session_db.php:58
#6: CSecuritySessionDB::read(string)
	
#7: session_start()
	/home/bitrix/shared-student/bitrix/modules/main/include.php:281
#8: require_once(string)
	/home/bitrix/shared-student/bitrix/modules/main/include/prolog_before.php:14
#9: require_once(string)
	/home/bitrix/shared-student/bitrix/modules/main/include/prolog.php:10
#10: require_once(string)
	/home/bitrix/shared-student/bitrix/header.php:1
#11: require(string)
	/home/bitrix/ext_www/XN--H1AAKGNRYD5B.XN--P1AI/catalog/index.php:2
#12: include_once(string)
	/home/bitrix/shared-student/bitrix/modules/main/include/urlrewrite.php:159
#13: include_once(string)
	/home/bitrix/shared-student/bitrix/urlrewrite.php:2