Using Outlook for iOS for personal email and calendar management
Thanks, that helps narrow it down.
Since Outlook still works on your old iPhone, could you check the old phone for me?
- Is Microsoft Authenticator still installed on the old iPhone? If so, does your Microsoft account appear there?
- When you try signing in on the new iPhone and choose "Approve a request on my Microsoft Authenticator app", does an approval request appear on the old iPhone?
It may be that Authenticator is still registered to the old phone rather than the new one.