Can't execute Query in EF6.3

I have the following query:

var result = await _dbContext.ApplicationItems.ToListAsync();

At runtime I get an exception on that query line:

I don't know why this exception is happening.

The class ApplicationItem looks like this:

public class ApplicationItem : EntityBase
{
    public List<ApplicationItemRole> ApplicationItemRoles { get; set; } = new List<ApplicationItemRole();
    public string AssemblyName { get; set; }
    public string ModuleName { get; set; }
    public string Name { get; set; }
    public string ViewModelType { get; set; }
}

and EntityBase has only one public property Id;