Critical Error

SQLSTATE[HY000] [2002] Connection refused

PDOException: SQLSTATE[HY000] [2002] Connection refused in /home/one/domains/one.ru/public_html/client/vendor/illuminate/database/Connectors/Connector.php:55
Stack trace:
#0 /home/one/domains/one.ru/public_html/client/vendor/illuminate/database/Connectors/Connector.php(55): PDO->__construct()
#1 /home/one/domains/one.ru/public_html/client/vendor/illuminate/database/Connectors/MySqlConnector.php(24): Illuminate\Database\Connectors\Connector->createConnection()
#2 /home/one/domains/one.ru/public_html/client/vendor/illuminate/database/Connectors/ConnectionFactory.php(61): Illuminate\Database\Connectors\MySqlConnector->connect()
#3 [internal function]: Illuminate\Database\Connectors\ConnectionFactory->Illuminate\Database\Connectors\{closure}()
#4 /home/one/domains/one.ru/public_html/client/vendor/illuminate/database/Connection.php(908): call_user_func()
#5 /home/one/domains/one.ru/public_html/client/vendor/illuminate/database/DatabaseManager.php(146): Illuminate\Database\Connection->getPdo()
#6 /home/one/domains/one.ru/public_html/client/vendor/illuminate/database/DatabaseManager.php(132): Illuminate\Database\DatabaseManager->refreshPdoConnections()
#7 /home/one/domains/one.ru/public_html/client/vendor/illuminate/database/DatabaseManager.php(197): Illuminate\Database\DatabaseManager->reconnect()
#8 [internal function]: Illuminate\Database\DatabaseManager->Illuminate\Database\{closure}()
#9 /home/one/domains/one.ru/public_html/client/vendor/illuminate/database/Connection.php(763): call_user_func()
#10 /home/one/domains/one.ru/public_html/client/vendor/illuminate/database/Connection.php(735): Illuminate\Database\Connection->reconnect()
#11 /home/one/domains/one.ru/public_html/client/vendor/illuminate/database/Connection.php(676): Illuminate\Database\Connection->tryAgainIfCausedByLostConnection()
#12 /home/one/domains/one.ru/public_html/client/vendor/illuminate/database/Connection.php(342): Illuminate\Database\Connection->run()
#13 /home/one/domains/one.ru/public_html/client/vendor/illuminate/database/Query/Builder.php(1583): Illuminate\Database\Connection->select()
#14 /home/one/domains/one.ru/public_html/client/vendor/illuminate/database/Query/Builder.php(1569): Illuminate\Database\Query\Builder->runSelect()
#15 /home/one/domains/one.ru/public_html/client/vendor/whmcs/whmcs-foundation/lib/Config/Setting.php(0): Illuminate\Database\Query\Builder->get()
#16 /home/one/domains/one.ru/public_html/client/vendor/whmcs/whmcs-foundation/lib/Application.php(0): WHMCS\Config\Setting::allAsArray()
#17 /home/one/domains/one.ru/public_html/client/vendor/whmcs/whmcs-foundation/lib/Application.php(0): WHMCS\Application->loadAdminDefinedConfigurations()
#18 /home/one/domains/one.ru/public_html/client/vendor/whmcs/whmcs-foundation/lib/Application/ApplicationServiceProvider.php(0): WHMCS\Application->__construct()
#19 /home/one/domains/one.ru/public_html/client/vendor/illuminate/container/Container.php(731): WHMCS\Application\ApplicationServiceProvider->WHMCS\Application\{closure}()
#20 /home/one/domains/one.ru/public_html/client/vendor/illuminate/container/Container.php(629): Illuminate\Container\Container->build()
#21 /home/one/domains/one.ru/public_html/client/vendor/illuminate/container/Container.php(1174): Illuminate\Container\Container->make()
#22 /home/one/domains/one.ru/public_html/client/vendor/illuminate/support/Facades/Facade.php(151): Illuminate\Container\Container->offsetGet()
#23 /home/one/domains/one.ru/public_html/client/vendor/illuminate/support/Facades/Facade.php(120): Illuminate\Support\Facades\Facade::resolveFacadeInstance()
#24 /home/one/domains/one.ru/public_html/client/vendor/whmcs/whmcs-foundation/lib/Application/Support/Facades/Facade.php(0): Illuminate\Support\Facades\Facade::getFacadeRoot()
#25 /home/one/domains/one.ru/public_html/client/init.php(0): WHMCS\Application\Support\Facades\Facade::self()
#26 /home/one/domains/one.ru/public_html/client/index.php(0): unknown()
#27 {main}