[Bitrix\Main\DB\SqlQueryException] 
Mysql query error: (2006) MySQL server has gone away (400)

				SELECT FROM_MODULE_ID, MESSAGE_ID, SORT, TO_MODULE_ID, TO_PATH,
					TO_CLASS, TO_METHOD, TO_METHOD_ARG, VERSION
				FROM b_module_to_module m2m
					INNER JOIN b_module m ON (m2m.TO_MODULE_ID = m.ID)
				ORDER BY SORT
			
/var/www/html/bitrix/modules/main/lib/db/mysqliconnection.php:137
#0: Bitrix\Main\DB\MysqliConnection->queryInternal(string, array, NULL)
	/var/www/html/bitrix/modules/main/lib/db/connection.php:329
#1: Bitrix\Main\DB\Connection->query(string)
	/var/www/html/bitrix/modules/main/lib/eventmanager.php:248
#2: Bitrix\Main\EventManager->loadEventHandlers()
	/var/www/html/bitrix/modules/main/lib/eventmanager.php:340
#3: Bitrix\Main\EventManager->findEventHandlers(string, string)
	/var/www/html/bitrix/modules/main/classes/general/module.php:340
#4: GetModuleEvents(string, string, boolean)
	/var/www/html/bitrix/modules/main/classes/general/access.php:25
#5: CAccess->__construct()
	/var/www/html/bitrix/modules/iblock/classes/mysql/iblock.php:102
#6: CIBlock::GetList(array, array)
	/var/www/html/local/modules/intervolga.custom/lib/iblock/IBlockHelper.php:25
#7: Intervolga\Custom\IBlock\IBlockHelper::getIdIblockByCode(string)
	/var/www/html/local/modules/intervolga.custom/constants.php:14
#8: require_once(string)
	/var/www/html/local/modules/intervolga.custom/include.php:12
#9: include_once(string)
	/var/www/html/bitrix/modules/main/lib/loader.php:109
#10: Bitrix\Main\Loader::includeModuleInternal(string)
	/var/www/html/bitrix/modules/main/lib/loader.php:96
#11: Bitrix\Main\Loader::includeModule(string)
	/var/www/html/local/php_interface/init.php:14
#12: include_once(string)
	/var/www/html/bitrix/modules/main/include.php:247
#13: require_once(string)
	/var/www/html/bitrix/modules/main/include/prolog_before.php:14
#14: require_once(string)
	/var/www/html/bitrix/click.php:3