Using Outlook for iOS in business environments for email and scheduling
Another version of this worked for me.
I am a completely non technical user with an office 365 account provided by my company and had transferred a personal domain to a new web hosting service and needed to re-set up the email account on Outlook. No issues with doing this on my PC but tried all sorts of settings when trying to set up on the Outlook app on iPhone and iPad.
This is what finally worked:
Deleted Outlook App from both iPhone and iPad and reinstalled it on iPhone.
Re-set up primary 365 account.
In settings added email account by entering email address
Next screen entered password, display name and description and turned on 'Use Advanced Settings' and clicked 'Sign in'
Next screen deleted port numbers including colons at the end of both the automatically populated IMAP & SMTP hostnames
Clicked sign in
Interestingly, after successfully testing incoming and outgoing emails, when I went back into settings the port numbers had repopulated.
Repeated same procedure for iPad which also worked.
I don't normally post on forums but the suggestions here helped me fathom it out so hope this helps someone too.