If Microsoft Edge detects SSL connection timeouts, certificate errors, or other network issues that may be caused by a captive portal (for example, a Wi-Fi network at a hotel or airport), Microsoft Edge sends a request to http://edge.microsoft.com/captiveportal/generate_204 and checks the response code. If the request is redirected to another URL, Microsoft Edge opens the URL in a new tab, assuming that it is a sign-in page. Requests to the captive portal detection page are a stateless service, requests are not logged, and cookies are not sent or saved. On Windows platforms, Microsoft Edge uses a Windows captive portal service. Otherwise, the Microsoft Edge captive portal service is used.
You can turn off this service with the Use a web service to help resolve navigation errors setting in Microsoft Edge.
You can also set to always enable or disable this service with the ResolveNavigationErrorsUseWebService policy.
This tutorial will show you how to enable or disable Use a web service to help resolve navigation errors in the Chromium based Microsoft Edge.