Environment: AWS / Microsoft Windows Server 2019 VM
A few .NET applications are running on a VM (as windows services), which make various HTTP requests. One of these is also using MQTT (via MQTTnet) to relay events from an external service to a different HTTP API.
Everything will work as expected for a few days, until finally HTTP requests from the applications start timing out.
Windows Event Viewer shows the following error every few minutes: "The WinHTTP Web Proxy Auto-Discovery Service service terminated with the following service-specific error: The endpoint mapper database entry could not be created."
At this point, seemingly any Win32/.NET application will fail to execute an HTTP request, including IE, etc — but not CURL. Likewise, other network connectivity and protocols seem fine. I'm assuming this would be due to an issue with WinHttp (or other low level Win32 HTTP services)? I've spent some time researching the Web Proxy Auto-Discovery service and trying to understand why it would suddenly start failing (and if it's the cause or just an effect), but I haven't found anything online.
I haven't found corrective action (restarting services, resetting things with netsh, etc) that will fix this condition. Only a full restart of windows seems to solve it. At which point the WinHTTP Web Proxy Auto-Discovery Service is happy again, http requests work again, etc.
I'm struggling to even find where to begin to troubleshoot this.
Best Answer
I had the same problem. I had disabled the services "WinHttpAutoProxySvc" and "iphlpsvc" in the instances that I had the problem . The service "iphlpsvc" depends on "WinHttpAutoProxySvc" and provides connectivity IPv6 over IPv4 (6to4). I haven't detected any problem with this action since last month and up to now.