Edit Server Settings for an Existing iOS 11 Mail Account

If you have already added a Mail Account to send/receive emails and have recently changed your email account password or have been moved to another server, you will need to update the settings in your iOS device for your email to continue to work.

Rather than removing the account and re-adding it with the updated settings, you can simply update your existing Mail Account settings through the Accounts & Passwords Settings section.

In this guide, you will learn how to modify the Incoming Server and Outgoing Server settings of an existing Mail Account on your iPad, iPhone, or iPod (running iOS 11).

https://www.raramuridesign.com/kb/articles/me-edit-server-settings-for-an-existing-ios-11-mail-account.html