I've just started having problems sending emails on my Mac and iPhone. Do you know why?
On June 26, 2013 Rackspace made some enhancements to their security and as a result, are no longer supporting a connection type called CRAM-MD5 for SMTP. Rackspace's testing shows that most mail clients will handle this change gracefully. However, Apple Mail, Thunderbird, Windows 8 Mail, and possibly some iPhone users will be unable to send messages until they update their settings.
Here are the instructions to change you SMTP settings:
While this change is inconvenient, Rackspace believes the long-term gains in user security make it absolutely necessary.
Modern Retail highly recommends you configure your email account using IMAP. An IMAP account leaves a copy of your email messages on the server, allowing you to synchronize messages between multiple devices. You will want to use an IMAP connection if you need to access your email at more than one location or device.
Date Created: 06/30/13