The best way to keep outgoing mail functioning efficiently in email software such as Outlook is to configure your email accounts with the outgoing mail settings of your internet service provider (ISP).
Popular ISPs are listed below.
Optus
mail.optusnet.com.au (port 25)
No Authentication
Telstra BigPond
mail.bigpond.com (port 465)
Use Authentication
Encrypted Connection: SSL Encryption
Outgoing mail server username: Your BigPond email address
Outgoing mail server password: Your BigPond account password
iiNet
mail.iinet.net.au (port 25)
No Authentication
Vodafone
smtp.vodafone.net.au (port 25)
If your ISP is not listed, the best thing to do is to contact them directly, or search in Google "[ISP name] outgoing mail settings".
For mobile devices, please contact your provider to get the correct outgoing mail server settings. They may also need to allow your device to send emails through their network as well.
The extensive range of email software and the number of different version numbers and computer operating systems mean that we are unable to offer tutorials for every program. If you need instructions on setting up emails in software such as Outlook or Apple Mail, the best thing to do is to contact the software company's support department, or to Google your email program, for example "how to set up email accounts in Outlook 2013".