Prestashop is an application that requires a functional domain name to work. During the installation, you should have been prompted with the domain name configuration and Prestashop was configured with that one.
I suggest you reinstall the PrestaShop stack and pay attention during the installation for this setting. Once you are asked to enter a valid domain name you could add 127.0.0.1 so you are able to access from localhost.
I hope it helps,