[PrestaShopException]

Link to database cannot be established:SQLSTATE[HY000] [2006] MySQL server has gone away
at line 118 in file classes/db/DbPDO.php

113.     {
114.         try {
115.             $this->link = $this->_getPDO($this->server, $this->user, $this->password, $this->database, 5);
116.         } 
117.         catch (PDOException $e) {
118.             throw new PrestaShopException('Link to database cannot be established:'.$e->getMessage());
119.         }
120. 
121.         // UTF-8 support
122.         if($this->link->exec('SET NAMES \'utf8mb4\'') === false) {
123.             throw new PrestaShopException('Fatal error: no utf-8 support. Please check your server configuration.');