Using Outlook for iOS for personal email and calendar management
Just add your email account to your I phone using the Apple Mail app.
it will work much better which ever server you use.
Dont use the outlook app.
My experience shows that the outlook app only works with a microsoft outlook email account.
I have tried using a few different servers including BT which is my main one. They just lock up on outlook app.
Stick with setting up your email using the apple mail app. Its easy to set up and will work no problem
i use micro soft 365 for all my work stuff and and apple mail app works with no issues.