Hey jartansmom,
Thanks for the question. You may need to configure the outgoing mail server for the account. The following resource will outline how to navigate to these settings, however instead of adding a server, you’ll then want to update the settings with your correct username and password:
iOS: Configuring additional outgoing mail servers
http://support.apple.com/kb/HT4519
1. Tap Settings > Mail, Contacts, Calendars.
2. Tap the Mail account for which you would like to change the settings. If you configured your account using any of the built-in presets, IMAP, or Exchange, you may need to tap Account Info on the following screen.
3. On the Account Info screen, locate the Outgoing Mail Server section and tap the existing SMTP entry. A list of SMTP servers will appear with the Primary Server and Other SMTP Servers.
If you need help with your mail settings, you can utilize this tool:
Mail Settings Lookup - Apple Support
https://ssl.apple.com/support/mail-settings-lookup/
Thanks,
Matt M.