I can't use class on layered architecture

Question

I'm working on a web.api for library otomation project.

I'm using layered architecture on project.

a485553e-89a6-4fa9-8dd5-1c40de6d40e2.jpg image is my architecture. I couldn't access User.cs class on DataAccess layer.

I defined with "usign" but it didn't work. I guess EntityFramework isn't work my project or ı can't add it

Answer 1

it's my problem "using" not work.

Answer 2

either the project Entities namespace is not Entities, the Entities namespace only has other namespaces, or there is not a project reference to it.