I setup a website in windows server 2016, with plesk and php 7 and phalcon 3.4
but I get this error
Uncaught Error: Class 'Phalcon\DI\FactoryDefault'
seems like phalcon is not installed / configured properly ?
phpinfo(); -> and search for phalcon there to make sure its running
No, that is a common erorr with Window$ OS and Apache / mod_php.
If you really really need to run app on Windows - you have to switch to PHP-CGI or to use NGINX and PHP-FPM (best scenario).