Hello @Cyrus,
Please find your answers as follows:
1. You can actually use your won SMTP but maybe you got confused to see the google SMTP help text. This is just a help text actually-> http://prntscr.com/ln38sd
2. I’m sorry but not sure why you are getting authentication failing issue but this is not something usual. In would be very great if you can contact our support center.
Regards
