Message : 500 Server Error

Bonjour,
Plus d'accès au site web ni au backoffice Prestashop.
Quelqu'un pourrait il me renseigner ?
Faut il attendre ? Panne serveur OVH ? ou faut il faire une démarche ?
Voici les messages :
Message pour accéder au site :
**_500 Server Error_**
**_Oops, something went wrong._**
**_Try to refresh this page or feel free to contact us if the problem persists._**

Message pour accéder au backoffice Prestashop :
[PrestaShopException]

Link to database cannot be established:SQLSTATE[HY000] [2002] php_network_getaddresses: getaddrinfo failed: Name or service not known
at line 102 in file classes/db/DbPDO.php

97. public function connect()
98. {
99. try {
100. $this->link = $this->_getPDO($this->server, $this->user, $this->password, $this->database, 5);
101. } catch (PDOException $e) {
102. throw new PrestaShopException('Link to database cannot be established:'.$e->getMessage());
103. }
104.
105. // UTF-8 support
106. if ($this->link->exec('SET NAMES \'utf8\'') === false) {
107. throw new PrestaShopException('PrestaShop Fatal error: no utf-8 support. Please check your server configuration.');


Merci, Dominique