I have a Cisco CP-8865-3PCC and accidentally changed the connection method from HTTP to HTTPS and am now unable to access the phone's web server. Upon typing in its IP address, my browser (Microsoft Edge) just tells me "This page isn't working right now <IP address> didn't send any data." If someone could help me regain access to my phone's web server without having to factory reset the phone, that would be much appreciated. Thanks!
Dumb question: Have you tried to type "https://<ip>" instead in the browser? I'm not sure, if the phone does a redirect to https, so after you have set the web access to https, the http port is not reachable anymore. Therefore you get the error message in the browser.