Network troubles might sometimes make it difficult to send or receive emails on any device. If you receive an error message stating that the email was not sent, check your Outbox because that email will be saved there and you can resend it from there. To check your Outbox for any unsent emails, follow these steps:

1. Open the Mail application.
2. Tap Mailboxes in the upper-left corner of the Mail app's screen.
3. Accounts is located at the bottom of the page.
4. After selecting your email account, press Outbox. If the email you're trying to send doesn't appear in your Outbox, it was sent successfully. If not, move on to the next step.
5. In the Outbox, tap an email. Check to see whether you've entered the correct information.email address of the email recipient.
6. Finally, tap Send to resend the email.