It seems that you haven’t created the menu, so please follow the following steps to fix your issue:
Go to Dashboard => Appearance => Menu => Then Add the menu => and click in the Primary menu in the Menu Setting => save it.
We hope this will be helpful to you, if not then please let us know, we are happy to provide solution asap.
With our premium themes, we offer access to site documentation, video tutorials and timely support. Even if you have just started on WordPress, our support staff have the patience to help you create appealing sites gracefully.