There are 2 options for remedying this...
1. Change your outgoing (SMTP) server to the one provided by your ISP
This will not affect the way your mail looks or the way your mail is delivered, and when the recipient replies, it will still go to your domain as normal. The only difference is the server the mail is being sent from.
Your ISP (Telstra, Optus, iinet etc.) should have provided you with the address of their outgoing server. If they haven't, you will need to contact them to find out.
2. Update the settings in your email program
The outgoing server settings can be found in the "Advanced" section when editing the properties of an email account.
You will need to open any messages stuck in your Outbox, and try to send them again.
- From the Menu Bar, Click Tools then Click E-mail Accounts
- Select "View or change existing e-mail accounts" then Click "Next"
- Select your Email account then Click "Change"
- Make sure both your incoming and outgoing servers are "mail.spiffystores.com"
- Click "More settings"
- Select "Outgoing Server" tab
- Select the box beside "My outgoing server (SMTP) requires authentication"
- Select "Use same settings as my incoming email server"
- Select the "Advanced" tab
- Change the "Outgoing server (SMTP)" port to 465 and tick the "SSL" box for your outgoing server.
- Click "Ok", then "Next" and then "Finish".
- Quit Outlook and then re-open it.
- You will need to open any messages stuck in your Outbox, and try to send them again.
- From the Menu Bar, Click Tools, then Account Settings.
- This will bring up the Account Settings window.
- Click on Outgoing Server (SMTP) at the bottom of the list on the left side of the window.
- Back in the middle of the window, select the appropriate outgoing server and click the "Edit" button.
- Change the Port number to 465.
- Make sure "Authentication method" is set to "Normal password" and the "User Name" field has your full email address.
- Make sure "Connection Security" is set to "SSL/TLS"
- Click OK to close the SMTP edit window and again on the Account Settings window.
- Quit Thunderbird and then re-open it.
- Try sending a message. Thunderbird may ask you to enter your password. If you enter the correct password, your message should send fine.
- From within Mac Mail Click Mail, Preferences, then Accounts
- If you have more than 1 account, select the account on the left of the window.
- Near the bottom of the window, look for Outgoing Mail Server (SMTP)
- Click the drop down arrow and select "Edit SMTP Server List..."
- Click the Advanced button in the middle of the window and make sure Authentication is set to "Password."
- Ensure that you have selected "Use default ports".
- Ensure that "Use Secure Sockets Layer (SSL)" is ticked.
- Make sure you have entered your full email address.
- Re-type your password (even if it already appears to be there!)
- Click OK to close the edit window.
- Enter your password for your INCOMING SERVER again (important!!!).
- Close the window making sure that you save your changes.
- Quit Mail and then re-open it.
If you still can't send mail after following these steps, please change the outgoing port number to 465 in step 6.
Please Note: We provide online tutorials to help you configure your email software as a courtesy. However, our support staff are unable to provide any support on how to use or configure third-party software on your computer, laptop, tablet or smartphone. We will provide support for any issues relating to the software and services on our servers, but you will need to contact the software manufacturer or visit their relevant online support pages for help with the software that they provide.