This article explains how to change or add an SMTP server for an email account. The information in this article applies to macOS Big Sur (11) through OS X Lion (10.7).
Outgoing Email Issues on Mac
Several popular email providers, including Google, Yahoo, Exchange, and AOL, come preconfigured with a default SMTP server on Macs. Not all email providers do. You may never need to change the default mail server listed for an account, but you may be required by your ISP or employer to use a preferred SMTP server.
To set a preferred outgoing SMTP mail server for an account in the Mail app, follow these steps:
Open the Mail application by clicking its icon in the Dock.
