I've just moved to an iphone 11 from android. I have a corporate Office 365 account, which I've configured on the iPhone. I used Outlook for IOS first, but am using the native mail and calendar apps now. The problem exists with either app. EMail syncs correctly both directions. Office 365 calendar appointments which I put into Outlook on my desktop appear fine on the iPhone, but appointments created on my iPhone never sync back to Office 365.
2 things you can check.
Settings - calendar - default calendar - if you want you can change it to outlook.
Second if you have multiply accounts, when you create an event on your phone make sure you set it for exchange account - in the calendar tab.
Thanks, but both are correct. I checked Settings - Calendar - default Calendar, and it's set to Exchange/Calendar
I have an Exchange and a GMail account (and an iCloud, I guess). When I create a test event, the default comes up correct, but if I check it, it's Exchange/Calendar.
Thanks
iphone calendar not syncing to office 365
