Wednesday, February 3, 2021

.NET Web API: Confusing 404 Response to OPTIONS Request for CORS pre-flight

Problem: when a Angular applications sends an OPTIONS request to its own backend to satisfy CORS preflight policy it unexpectedly receives a 404 response from a .NET Core Web API application that effectively blocks an actual data data request from executing correctly. If you have ever experienced this problem, continue reading to understand what the problem is and how to fix it.