Could not load type 'SafariTest2017.TestPage2'

I am using Visual Studio 2017 to create a web site and get the above error on new pages only. The pages that were included (default, About & Contact) load as expected, but any page I create get the same error.

I only get the error on the remote host, they load fine in the local test host.

I am using the publish upload function.

I am an occasional user and have no idea where to look.  It’s probably a simple setting I have missed. 

What other information can I provide?

Test Page 2 will not load

<%@ Page Title="Test Page 2" Language="C#" MasterPageFile="~/Site.Master" AutoEventWireup="true" CodeBehind="TestPage2.aspx.cs" Inherits="SafariTest2017.TestPage2" %>
<asp:Content ID="Content1" ContentPlaceHolderID="MainContent" runat="server">
Test Page 2
</asp:Content>

The pages that were included load fine, like the Default page below.

The Default page has not problem.

<%@ Page Title="Home Page" Language="C#" MasterPageFile="~/Site.Master" AutoEventWireup="true" CodeBehind="Default.aspx.cs" Inherits="SafariTest2017._Default" %>

Thanks in advance.

John