I have an issue regarding SMTP setting of Gmail, Yahoo and Outlook. I am unable to send email addresses via these SMTP settings.
You will need to configure all three services before you can use them.
For Gmail: First, log on the web through a browser and access the Settings > Forwarding and POP. Enable POP and IMAP, then use the information on the page to use the custom SMTP settings provided by Gmail.
For Yahoo: Yahoo doesn't have SMTP settings, unless you're in ASIA where the service is available for free. However, I see they've recently removed this limitation. Use the following page to see the correct settings: https://help.yahoo.com/kb/SLN4724.html
For Outlook: Check the following page to obtain the SMTP settings: http://windows.microsoft.com/en-us/windows/outlook/send-receive-from-app