[Bitrix\Main\DB\SqlQueryException] 
Mysql query error: (2006) MySQL server has gone away (400)
SELECT GET_LOCK("d7e7bd7d702b7d4db92035487383ebec", 60)
LIMIT 0, 1

/home/bitrix/www/bitrix/modules/main/lib/db/mysqliconnection.php:137
#0: Bitrix\Main\DB\MysqliConnection->queryInternal(string, NULL, NULL)
	/home/bitrix/www/bitrix/modules/main/lib/db/connection.php:330
#1: Bitrix\Main\DB\Connection->query(string, NULL, integer, integer)
	/home/bitrix/www/bitrix/modules/main/lib/db/connection.php:358
#2: Bitrix\Main\DB\Connection->queryScalar(string)
	/home/bitrix/www/bitrix/modules/security/lib/session.php:114
#3: Bitrix\Security\SessionTable::lock(string, integer)
	/home/bitrix/www/bitrix/modules/security/classes/general/session_db.php:52
#4: CSecuritySessionDB::read(string)
	/home/bitrix/www/bitrix/modules/security/classes/general/session_handler.php:23
#5: CSecuritySessionHandler->read(string)
	
#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(string)
	/home/bitrix/www/bitrix/tools/captcha.php:8