I was having issues retrieving and sending mail via Hotmail on an older windows 8.1 system, did several network traces and found it connecting to m.hotmail.com and I saw a thread somewhere where they suggested changing it to eas.outlook.com but there was no way for me to change it, couldn't find any options anywhere to change it so i tried removing and reconfiguring the account removing and reinstalling the app and i didn't want to switch to a different app, so i resorted to the registry. That fixed the problem for me.