whole story came here:
XF 1.5 - GMail Smtp SSL Could not open socket on an ubuntu XAMPP Server
finally I installed xampp-linux-x64-5.5.24-0-installer.run with php version:
PHP 5.5.24 (cli) (built: Apr 20 2015 19:39:09)
Copyright (c) 1997-2015 The PHP Group
Zend Engine v2.5.0, Copyright (c) 1998-2015 Zend Technologies
zend send is okay, So PHP 5.6.8 can not work with xenforo 1.5.
XF 1.5 - GMail Smtp SSL Could not open socket on an ubuntu XAMPP Server
finally I installed xampp-linux-x64-5.5.24-0-installer.run with php version:
PHP 5.5.24 (cli) (built: Apr 20 2015 19:39:09)
Copyright (c) 1997-2015 The PHP Group
Zend Engine v2.5.0, Copyright (c) 1998-2015 Zend Technologies
zend send is okay, So PHP 5.6.8 can not work with xenforo 1.5.