iPhone mail app won’t connect to office 365

Dear Dave Burns2

Thanks for using Microsoft products and posting in the community. 

I understand that you cannot connect to your mailbox in Apple's Mail app, and the software prompts that the account already exists.

This seems to be that the software itself has not been configured cleanly.

What is your account domain name (email address suffix)? When configuring email in Apple Mail, what email protocol did you choose, IMAP, POP, Outlook.com? Please share detailed information with us to help us understand the problem intuitively.

Try to log in to your account in other ways, such as using a browser to access your mailbox, and check whether your account status is normal. You can try to download other email software (such as Outlook App) on your phone to see if you can successfully connect to your mailbox in other email software.

If you can connect to your mailbox in other email apps or browsers, it means that there may be a problem with the mail app itself, or the problem caused by the phone system update cannot be ruled out.

1. You can try to clear the cache in your browser, update your mail app, and see if you can successfully connect to your mailbox.

The browser will automatically save temporary Internet files to help speed up page loading. Clearing this cache can sometimes solve page display problems. Please back up important data first to avoid data loss.

2. You can try to uninstall and reinstall the mail app, and then shut down and restart your phone. See if you can successfully connect to your mailbox.

3. You can provide feedback about this issue to the mail app and try to contact the mail app technical support for help.

Thank you for your patience and support. Looking forward to your follow-up reply.

Have a great day.

Sincerely,

Forry.F - MSFT | Microsoft Community Support Specialist