Table 'AspNetUsers' does not have the identity property. Cannot perform SET operation

I am trying to convert a 10+ year old database to our new format and using EFCore to do the ETL. And here is the method that is throwing me an error on.

internal void GetAllUsers(string? userName = null) {
            List<AspNetUser> oldUsers = new List<AspNetUser>();

            if (userName is not null)
            {
                oldUsers = _oldContext.AspNetUsers.Where(x => x.UserName == userName).ToList();
                //if (!oldUsers.Any()) Console.WriteLine("No Users Found Exiting");
                //return;
            }
            if (userName is null) oldUsers.AddRange(_oldContext.AspNetUsers.OrderBy(x => x.Id));
            foreach (var user in oldUsers) {
                var newUser = ConvertAspNetUserToConnexUser(user);
                Console.WriteLine($"Converting user: {0}", newUser.UserName);
                CreateUserConnections(ref newUser);
                CreateLicenseKey(newUser);
                CreateTaxCodes(newUser);
                if (_newContext.ConnexUsers.Any(x => x.Id == newUser.Id))
                    newUser.Id = Guid.NewGuid().ToString();
                _newContext.ConnexUsers.Add(newUser);
                AnsiConsole.WriteLine($"Inserting user: {0} to the new database.", newUser.UserName);
                try {
                    _newContext.Database.OpenConnection();
                    _newContext.Database.ExecuteSqlRaw("SET IDENTITY_INSERT [AspNetUsers] ON");
                    _newContext.SaveChanges();
                    _newContext.Database.ExecuteSqlRaw("SET IDENTITY_INSERT [AspNetUsers] OFF");
                } catch (Exception ex) {
                    Console.WriteLine(ex.ToString());
                    AnsiConsole.WriteLine($"Problem Inserting {user. Email}");
                    throw new Exception($"Problem inserting the user {newUser.Email}: ", ex);
                } finally {
                    _newContext.Database.CloseConnection();
                }
            }
            
        }

This is the user object that I have for our users.

public class CustomUser : IdentityUser
{
    [Display(Name = "First Name")]
    public string FirstName { get; set; }
    [Display(Name = "Last Name")]
    public string LastName { get; set; }
    [Display(Name = "Company")]
    public string Company { get; set; }
    [Display(Name = "Title")]
    public string Title { get; set; }
    public DateTime DateInserted { get; set; }
    public DateTime DateModified { get; set; }
    public ICollection<RuleSet> RuleSets { get; set; } = new List<RuleSet>();
    public ICollection<UserCompany> UserCompanies { get; set; } = new List<UserCompany>();
    public bool IsQuickBooksSandBox { get; set; }
    public string? ConnectionName { get; set; }

}

If I don't set IDENITITY_INSERT OFF then I will get another error as well

SqlException: Cannot insert explicit value for identity column in table 'UserConnections' when IDENTITY_INSERT is set to OFF.

Does anyone have any suggestions?