It the issue in new version,
follow just few steps, to resolve this issue
1. check your php version
i. php -v (if you using command line)
ii. Or use this code to check from web (
<?php
phpinfo();
?>
and note your php version
2. run these commands in terminal / command line
sudo a2enmod proxy_fcgi setenvif
sudo a2enconf php7.0-fpm #(your php version)
sudo service apache2 restart
It will works,
Thats it!