XF 2.0 Need Help! email not working

[Takao]

When I tried sending emails, i get the following error in the log.

Error: Class 'Pelago\Emogrifier' not found src/XF/App.php:826
Stack trace
#0 src/XF/Container.php(28): XF\App->XF\{closure}(Object(XF\Container))
#1 src/XF/App.php(777): XF\Container->offsetGet('mailer.styler')
#2 src/XF/Container.php(28): XF\App->XF\{closure}(Object(XF\Container))
#3 src/XF/App.php(2138): XF\Container->offsetGet('mailer')
#4 src/XF/Admin/Controller/Tools.php(231): XF\App->mailer()
#5 src/XF/Mvc/Dispatcher.php(249): XF\Admin\Controller\Tools->actionTestEmail(Object(XF\Mvc\ParameterBag))
#6 src/XF/Mvc/Dispatcher.php(88): XF\Mvc\Dispatcher->dispatchClass('XF:Tools', 'TestEmail', 'html', Object(XF\Mvc\ParameterBag), 'tools', Object(XF\Admin\Controller\Tools), NULL)
#7 src/XF/Mvc/Dispatcher.php(41): XF\Mvc\Dispatcher->dispatchLoop(Object(XF\Mvc\RouteMatch))
#8 src/XF/App.php(1931): XF\Mvc\Dispatcher->run()
#9 src/XF.php(328): XF\App->run()
#10 admin.php(13): XF::runApp('XF\\Admin\\App')
#11 {main}

I just uploaded the installation file to my server, installed XenForo 2, and setup my email.
I tried default email setting and SMTP, but either way, it gives me the same error.
Any advice is appreciated.

 

[TPerry]

Try uploading the files again... but be sure that you get the update files and not the full install files or you will overwrite some important ones.
And try using a different FTP client or if you have cPanel transfer the file to your site and extract it there and move them over.
If you are using FileZilla for transfers it has been known to have issues with not fully transferring files in the past.

 

[Takao]

I did full install one time and got the same result before.
But when I upgrade files, I no longer have error log. Thank you for your help!