[Bitrix\Main\DB\SqlQueryException] 
Mysql query error: (2006) MySQL server has gone away (400)
SELECT 1 FROM b_messageservice_message WHERE SUCCESS_EXEC='N' AND (NEXT_EXEC < '2019-08-22 19:33:06' OR NEXT_EXEC IS NULL) LIMIT 1
/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)
	/home/bitrix/www/bitrix/modules/messageservice/lib/queue.php:23
#2: Bitrix\MessageService\Queue::hasMessages()
	/home/bitrix/www/bitrix/modules/messageservice/lib/queue.php:43
#3: Bitrix\MessageService\Queue::run()
	/home/bitrix/www/bitrix/modules/main/classes/general/module.php:490
#4: ExecuteModuleEventEx(array)
	/home/bitrix/www/bitrix/modules/main/include/epilog_after.php:55
#5: require(string)
	/home/bitrix/www/bitrix/modules/main/include/epilog.php:3
#6: require_once(string)
	/home/bitrix/www/bitrix/footer.php:4
#7: require(string)
	/home/bitrix/www/catalog/index.php:623
#8: include_once(string)
	/home/bitrix/www/bitrix/modules/main/include/urlrewrite.php:159
#9: include_once(string)
	/home/bitrix/www/bitrix/urlrewrite.php:2