[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, NULL, NULL)
	/home/bitrix/www/bitrix/modules/main/lib/db/connection.php:330
#2: Bitrix\Main\DB\Connection->query(string, NULL, integer, integer)
	/home/bitrix/www/bitrix/modules/main/lib/db/connection.php:358
#3: Bitrix\Main\DB\Connection->queryScalar(string)
	/home/bitrix/www/bitrix/modules/main/lib/session/handlers/table/usersessiontable.php:100
#4: Bitrix\Main\Session\Handlers\Table\UserSessionTable::lock(string)
	/home/bitrix/www/bitrix/modules/main/lib/session/handlers/databasesessionhandler.php:50
#5: Bitrix\Main\Session\Handlers\DatabaseSessionHandler->lock(string)
	/home/bitrix/www/bitrix/modules/main/lib/session/handlers/abstractsessionhandler.php:50
#6: Bitrix\Main\Session\Handlers\AbstractSessionHandler->read(string)
	
#7: session_start()
	/home/bitrix/www/bitrix/php_interface/init.php:3
#8: include_once(string)
	/home/bitrix/www/bitrix/modules/main/include.php:139
#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:1
#12: require(string)
	/home/bitrix/www/catalog/index.php:1
#13: include_once(string)
	/home/bitrix/www/bitrix/modules/main/include/urlrewrite.php:159
#14: include_once(string)
	/home/bitrix/www/bitrix/urlrewrite.php:2