This problem began under 9.1 for me and continues with the first public beta of 9.2. I have Outlook for my own domain. I use the Apple Mail app, and the Outlook account is set up under the Mail app's own "Add Outlook.com account" option. Suddenly, under 9.1, my email stopped arriving. I received server connection errors, and password requests for my "Exchange" account. But it's not set up as an Exchange account. I added and re-added the account, reset phone, changed Outlook password and tried to re-add again, toggled two-factor identification and shuffled Outlook individual app passwords, etc. No dice. Is anyone else having this problem? I remember the 1990s when email apps worked with any email address.