[Bitrix\Main\DB\ConnectionException] 
Mysql connect error [localhost]: (2002) Connection refused (400)
/htdocs/www/bitrix/modules/main/lib/db/mysqliconnection.php:65
#0: Bitrix\Main\DB\MysqliConnection->connectInternal()
	/htdocs/www/bitrix/modules/main/lib/db/mysqliconnection.php:122
#1: Bitrix\Main\DB\MysqliConnection->queryInternal(string, array, NULL)
	/htdocs/www/bitrix/modules/main/lib/db/connection.php:330
#2: Bitrix\Main\DB\Connection->query(string)
	/htdocs/www/bitrix/modules/main/lib/modulemanager.php:20
#3: Bitrix\Main\ModuleManager::getInstalledModules()
	/htdocs/www/bitrix/modules/main/lib/loader.php:88
#4: Bitrix\Main\Loader::includeModule(string)
	/htdocs/www/bitrix/modules/main/lib/data/connectionpool.php:308
#5: Bitrix\Main\Data\ConnectionPool->createSlaveConnection()
	/htdocs/www/bitrix/modules/main/lib/data/connectionpool.php:247
#6: Bitrix\Main\Data\ConnectionPool->getSlaveConnection(string)
	/htdocs/www/bitrix/modules/main/lib/db/connection.php:318
#7: Bitrix\Main\DB\Connection->query(string)
	/htdocs/www/bitrix/modules/main/lib/config/option.php:226
#8: Bitrix\Main\Config\Option::load(string, NULL)
	/htdocs/www/bitrix/modules/main/lib/config/option.php:53
#9: Bitrix\Main\Config\Option::get(string, string, string)
	/htdocs/www/bitrix/modules/main/lib/httprequest.php:392
#10: Bitrix\Main\HttpRequest->prepareCookie(array)
	/htdocs/www/bitrix/modules/main/lib/httprequest.php:69
#11: Bitrix\Main\HttpRequest->__construct(object, array, array, array, array)
	/htdocs/www/bitrix/modules/main/lib/httpapplication.php:46
#12: Bitrix\Main\HttpApplication->initializeContext(array)
	/htdocs/www/bitrix/modules/main/lib/application.php:122
#13: Bitrix\Main\Application->initializeExtendedKernel(array)
	/htdocs/www/bitrix/modules/main/include.php:22
#14: require_once(string)
	/htdocs/www/bitrix/modules/main/include/prolog_before.php:14
#15: require_once(string)
	/htdocs/www/bitrix/modules/main/include/prolog.php:10
#16: require_once(string)
	/htdocs/www/bitrix/header.php:1
#17: require(string)
	/htdocs/www/index.php:2