[Bitrix\Main\DB\ConnectionException] 
Mysql connect error [localhost]: (2002) Connection refused (400)
/home/bitrix/www/bitrix/modules/main/lib/db/mysqliconnection.php:65
#0: Bitrix\Main\DB\MysqliConnection->connectInternal()
	/home/bitrix/www/bitrix/modules/main/lib/data/connection.php:53
#1: Bitrix\Main\Data\Connection->getResource()
	/home/bitrix/www/bitrix/modules/main/lib/db/mysqlisqlhelper.php:21
#2: Bitrix\Main\DB\MysqliSqlHelper->forSql(string)
	/home/bitrix/www/bitrix/modules/main/lib/eventmanager.php:167
#3: Bitrix\Main\EventManager->registerEventHandlerInternal(string, string, string, string, string, integer, string, string, integer)
	/home/bitrix/www/bitrix/modules/main/lib/eventmanager.php:156
#4: Bitrix\Main\EventManager->registerEventHandlerCompatible(string, string, string, string, string, string, string, array)
	/home/bitrix/www/bitrix/modules/main/classes/general/module.php:507
#5: RegisterModuleDependences(string, string, string, string, string, string)
	/home/bitrix/www/bitrix/php_interface/init.php:825
#6: include_once(string)
	/home/bitrix/www/bitrix/modules/main/include.php:234
#7: require_once(string)
	/home/bitrix/www/bitrix/modules/main/include/prolog_before.php:14
#8: require_once(string)
	/home/bitrix/www/bitrix/modules/main/include/prolog.php:10
#9: require_once(string)
	/home/bitrix/www/bitrix/header.php:1
#10: require(string)
	/home/bitrix/www/forum/index.php:2
#11: include_once(string)
	/home/bitrix/www/bitrix/modules/main/include/urlrewrite.php:159
#12: include_once(string)
	/home/bitrix/www/bitrix/urlrewrite.php:2