Ok, it took me the entire weekend to figure out why my smtp is not working. Finally solve. Fyi, I am hosting over my own network, locally. The problem was that my broadband service block the default smtp server port but not the alternative that my email use. But now whenever someone registered on my wordpress they received a email from the username of the email I specify shiftthis smtp. How can I change it to another email or to something else beside the username of my email?
Any help appreciated.