Extender Provider failed to return an Extender

Question

We upgraded from .NET 2.0 to .NET 3.5. A co-worker of mine is getting the following dialog when attempting to run the ASP .NET web project under the debugger in Visual Stud

Answer 1

In my case I had deleted 'SSL' from the VS2017 C# project properties debug configuration build tab Conditional compilation symbols. Putting it back resolved the error. Apparently SSL require in Debug configuration (but not release).