Up until 4/24 I was able to keep emails on my phone even after Outlook removed them from the web. Now as soon as they are removed, my emails on my phone vanish. I think my email was using a POP setting but was changed to IMAP by a tech. My phone automatically sets up IMAP when I try to set up an email account.
[Re-Titled by Moderator]
iPhone 6s, iOS 12
That sounds like your phone was switched from POP to IMAP. You will need to delete the account, then add it back as a POP account. That's a little tricky; here are some instructions-->Forcing creation of a POP or IMAP email a… - Apple Community
That sounds like your phone was switched from POP to IMAP. You will need to delete the account, then add it back as a POP account. That's a little tricky; here are some instructions-->Forcing creation of a POP or IMAP email a… - Apple Community
Something to note... not every provider supports POP. Your account may have been forced to IMAP.
Even as a POP account, you can still tell Outlook to leave retrieved emails on the server.
With Outlook open, choose Tools > Accounts… from the top menu bar. Click on the Advanced button at the lower right. Check the top box.
Except the phone had previously been a POP account, so unless the provider suddenly stopped supporting it at the same time a tech set up the phone as IMAP they probably still do.
Keep emails on my phone even after Outlook remove them from the web
