[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/db/mysqliconnection.php:122
#1: Bitrix\Main\DB\MysqliConnection->queryInternal(string, array, NULL)
	/home/bitrix/www/bitrix/modules/main/lib/db/connection.php:329
#2: Bitrix\Main\DB\Connection->query(string)
	/home/bitrix/www/bitrix/modules/main/lib/config/option.php:182
#3: Bitrix\Main\Config\Option::load(string, NULL)
	/home/bitrix/www/bitrix/modules/main/lib/config/option.php:53
#4: Bitrix\Main\Config\Option::get(string, string, string)
	/home/bitrix/www/bitrix/modules/main/lib/httprequest.php:337
#5: Bitrix\Main\HttpRequest->prepareCookie(array)
	/home/bitrix/www/bitrix/modules/main/lib/httprequest.php:63
#6: Bitrix\Main\HttpRequest->__construct(object, array, array, array, array)
	/home/bitrix/www/bitrix/modules/main/lib/httpapplication.php:42
#7: Bitrix\Main\HttpApplication->initializeContext(array)
	/home/bitrix/www/bitrix/modules/main/lib/application.php:122
#8: Bitrix\Main\Application->initializeExtendedKernel(array)
	/home/bitrix/www/bitrix/modules/main/include.php:23
#9: require_once(string)
	/home/bitrix/www/bitrix/modules/main/include/prolog_before.php:14
#10: require_once(string)
	/home/bitrix/www/bitrix/modules/main/include/prolog.php:10
#11: require_once(string)
	/home/bitrix/www/bitrix/header.php:2
#12: require(string)
	/home/bitrix/www/kourse/index.php:2