If you're getting this error when attempting to send email, try the following:

For Outlook

1. Click "Tools" and then "Email Accounts"
2. Select "View or Change Existing Email Accounts" and click "Next"
3. Select the email account and click "Change"
4. Click on "More settings"
5. Select "Outgoing Server" tab
6. Tick "My outgoing server (SMTP) requires authentication"
7. Select "Use Same Settings As My Incoming Email Server"
8. Click "OK"
9. Press "Next"
10. Lastly, press "finish"

Once these steps are done, try to sending the email again.

If you run into further issues, please get in touch with our support team.