Computers communicate using different protocols, which are much like spoken languages. SMTP, or simple mail transfer protocol, is often used to send email messages. An SMTP server is a computer configured to read and understand these messages and then pass them on to their intended recipient. When setting up an email account on your iPhone, you need to use the correct SMTP server settings to ensure your messages get to the right place.

Finding the Correct Server

Each email provider's SMTP server address is different. Typically, though not always, they follow this format: “smtp.provider.com”. To give a few commonly used examples, hotmail's server is “smtp.live.com”, Gmail's is “smtp.gmail.com”, and Yahoo's is “mail.yahoo.com.” If you don't use these, contact your provider's customer support to find out your server address.

Changing the SMTP Server

To change your SMTP server, tap “Settings” from the home screen and then tap “Mail, Contacts, Calendars.” Tap the name of the account you want to change, "Account Info" and then tap "Outgoing Mail Server." From here, tap the SMTP entry, enter the SMTP server address and then tap “Save.”