Issue with Identity on Upgraded ASP.Net Core Project

I upgraded an ASP.Net Core project to Core 2.  I want to remove Identity from it because I no longer need authentication.  I am getting the following error when I attempt to display the 1st page:

An unhandled exception occurred while processing the request.

InvalidOperationException: No service for type 'Microsoft.AspNetCore.Identity.UserManager`1[SP_Common_Classes.Models.ApplicationUser]' has been registered.

Let me know if you need any additional supporting code.

Thanks in advance,

Mark Lindahl