Problem with the site

The site died unexpectedly. I assume a problem with the database of this. The site is based on CMS 1C Bitrix
inference:
[BitrixMainDBConnectionException]
Mysql connect error [localhost]: (2002) No such file or directory (400)
/var/www/u0242979/data/www/ngshop.ru/bitrix/modules/main/lib/db/mysqliconnection.php:65
#0: BitrixMainDBMysqliConnection->connectInternal()
/var/www/u0242979/data/www/ngshop.ru/bitrix/modules/main/lib/db/mysqliconnection.php:122
#1: BitrixMainDBMysqliConnection->queryInternal(string, array, NULL)
/var/www/u0242979/data/www/ngshop.ru/bitrix/modules/main/lib/db/connection.php:329
#2: BitrixMainDBConnection->query(string)
/var/www/u0242979/data/www/ngshop.ru/bitrix/modules/main/lib/config/option.php:226
#3: BitrixMainConfigOption::load(string, NULL)
/var/www/u0242979/data/www/ngshop.ru/bitrix/modules/main/lib/config/option.php:53
#4: BitrixMainConfigOption::get(string, string, string)
/var/www/u0242979/data/www/ngshop.ru/bitrix/modules/main/lib/httprequest.php:337
#5: BitrixMainHttpRequest->prepareCookie(array)
/var/www/u0242979/data/www/ngshop.ru/bitrix/modules/main/lib/httprequest.php:63
#6: BitrixMainHttpRequest->__construct(object, array, array, array, array)
/var/www/u0242979/data/www/ngshop.ru/bitrix/modules/main/lib/httpapplication.php:42
#7: BitrixMainHttpApplication->initializeContext(array)
/var/www/u0242979/data/www/ngshop.ru/bitrix/modules/main/lib/application.php:122
#8: BitrixMainApplication->initializeExtendedKernel(array)
/var/www/u0242979/data/www/ngshop.ru/bitrix/modules/main/include.php:23
#9: require_once(string)
/var/www/u0242979/data/www/ngshop.ru/bitrix/modules/main/include/prolog_before.php:14
#10: require_once(string)
/var/www/u0242979/data/www/ngshop.ru/bitrix/modules/main/include/prolog.php:10
#11: require_once(string)
/var/www/u0242979/data/www/ngshop.ru/bitrix/header.php:1
#12: require(string)
/var/www/u0242979/data/www/ngshop.ru/index.php:2