Outlook supports IMAP, not POP3. https://support.office.com/en-us/article/Set-up-email-on-iPhone-iPad-or-iPod-Touch-b2de2161-cc1d-49ef-9ef9-81acd1c8e234#BKMK_IM

Outlook supports IMAP, not POP3. https://support.office.com/en-us/article/Set-up-email-on-iPhone-iPad-or-iPod-Touch-b2de2161-cc1d-49ef-9ef9-81acd1c8e234#BKMK_IMAPorPOP https://support.office.com/en-us/article/Set-up-email-on-iPh...