Configure your WP Advanced Email Options as follows:
smtp.gmail.com / 465 / Use SSL encryption / Use SMTP authentication
Send a test message. If you are getting:
Could not connect to SMTP host.
Unable to find the socket transport "ssl" -
did you forget to enable it when you configured PHP?
you need to check phpinfo(). Search for openSSL.
If it is not installed and enabled you need to install it.
Rerun latest PHP install, make sure you picked OpenSSL extension.
Double check, if these lines added to your php.ini:
Remember to restart your WEB server.