Apple Mail error: Cannot send message using the server

You may see an error message in Apple Mail that says:

Cannot send message using the server [server address]
The sender address [your email address] was rejected by the server [server address]

1. If you have the option on the error message, click Edit SMTP Server List.

Note: If you don’t have the error open, or don’t see this option: Select your account under Inbox, click the cog under the mailbox list, and select Edit “[your email address]”… Then click the menu next to Outgoing Mail Server (SMTP), and select Edit SMTP Server List…

2. Select the server in use by your account.
3. If you have multiple servers with the same name, you will need to remove the duplicates. Select the duplicate server, then click — below the list.
4. Click Advanced.
5. Make sure all the fields match your correct settings:

6. Click OK.
7. If you are returned to the error message, select the server you just edited, and click Try With Selected Server.

More info

• Add my email to Apple Mail
• Troubleshooting Apple Mail
• Update existing account settings in Apple Mail