prestashop error Problem: Admin/Backend login redirect in version 1.6

1/ Clear your browser cache and your cookies 2/ Try using Firefox instead of Chrome (which seems have some unexpected problems) 3/ Check PS_SHOP_DOMAIN and PS_SHOP_DOMAIN_SSL in ps_configuration table 4/ Manually clear smarty cache : remove all files from tools/smarty/compile and tools/smarty/cache 5/ Disable the IP check in classes/Cookie.php (this can causes many issues with dynamics IP) : in isLoggedBack(), remove or comment the fourth condition : AND (!isset($this->_content['remote_addr']) OR $this->_content['remote_addr'] == ip2long(Tools::getRemoteAddr()) OR !Configuration::get('PS_COOKIE_CHECKIP')) 6/ Make the expire time shorter for cookies (IE can have issues with longest time cookies) : in classes/Cookie.php constructor, set : $this->_expire = isset($expire) ? (int)($expire) : (time() + 3600); instead of $this->_expire = isset($expire) ? (int)($expire) : (time() + 1728000);