Site e-commerce

Bonjour, je viens d'importer une Bdd créée sous prestashop 1.6 pour l'utiliser sous prestashop 1.8
Malgré la vérification des éléments de connection dans parameters.php j'ai me message suivant :
Link to database cannot be established:SQLSTATE[HY000] [2002] Connection refused
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.');
DbPDOCore->connect - [line 319 - classes/db/Db.php]
DbCore->__construct - [line 239 - classes/db/Db.php] - [4 Arguments]
DbCore::getInstance - [line 66 - config/alias.php]
pSQL - [line 329 - classes/shop/Shop.php] - [1 Arguments]
ShopCore::initialize - [line 114 - config/config.inc.php]
require - [line 39 - admin/index.php] - [1 Arguments]

J'aimerai donc pouvoir me connecter à ma BDD pour finir la migration de mon site
merci
cdt