Found a couple of things. The reason I was getting the ERR_TOO_MANY_REDIRECTS, was due to the system looking for a PageNotFound view and there wasn't one. So added one and that fixed that problem.

Loading the UserList page was giving the Status Code: 302 Found. This was a middleware problem -

Category: Microsoft.AspNetCore.Diagnostics.ExceptionHandlerMiddleware EventId: 1 SpanId: 2ff3e9926a1b6c03 TraceId: 7314731274212a962b5c1323b0299200 ParentId: 0000000000000000 RequestId: 400070d4-0005-f900-b63f-84710c7967bb RequestPath: /UserAdmin/UserList An unhandled exception has occurred while executing the request.

The problem was System.InvalidOperationException: There is already an open DataReader associated with this Connection which must be closed first.

This was solve by adding

 MultipleActiveResultSets=True

to the connection string.

Thank you for your help.