[Bitrix\Main\DB\ConnectionException] 
Mysql connect error [localhost]: (2002) Connection refused (400)
/var/www/clients/client0/web1/web/bitrix/modules/main/lib/db/mysqliconnection.php:65
#0: Bitrix\Main\DB\MysqliConnection->connectInternal
	/var/www/clients/client0/web1/web/bitrix/modules/main/lib/db/mysqliconnection.php:122
#1: Bitrix\Main\DB\MysqliConnection->queryInternal
	/var/www/clients/client0/web1/web/bitrix/modules/main/lib/db/connection.php:330
#2: Bitrix\Main\DB\Connection->query
	/var/www/clients/client0/web1/web/bitrix/modules/main/lib/eventmanager.php:242
#3: Bitrix\Main\EventManager->loadEventHandlers
	/var/www/clients/client0/web1/web/bitrix/modules/main/lib/eventmanager.php:340
#4: Bitrix\Main\EventManager->findEventHandlers
	/var/www/clients/client0/web1/web/bitrix/modules/main/classes/general/module.php:340
#5: GetModuleEvents
	/var/www/clients/client0/web1/web/bitrix/modules/main/include.php:280
#6: require_once(string)
	/var/www/clients/client0/web1/web/bitrix/modules/main/include/prolog_before.php:14
#7: require_once(string)
	/var/www/clients/client0/web1/web/bitrix/modules/main/include/prolog.php:10
#8: require_once(string)
	/var/www/clients/client0/web1/web/bitrix/header.php:1
#9: require(string)
	/var/www/clients/client0/web1/web/404.php:5
#10: include_once(string)
	/var/www/clients/client0/web1/web/bitrix/urlrewrite.php:4