This article explains how to fix the Cannot Send Mail. ‘rejected by the server because it does not allow relaying’ message.
Applies to iOS all versions.
- Go to Settings > the next menu depends on your version of iOS. It will be one of these;
Password & Accounts (iOS13)
Password and Accounts (iOS12) or
Accounts & Passwords (iOS11) or
Mail, Contacts, Calendar (iOS9/iOS10) and earlier.
- Tap on your mail box in the Account section, then on the next page tap it again to bring up the full details.
- Go down to the Outgoing Mail Server section and tap on SMTP.
- Tap on your Primary Server.
- Set Authentication to Password if not already selected.
- Even though it says Optional, fill out both user name and password under Outgoing Mail Server.
- Tap Done in the top right to save your changes.
- You can now send emails.