Fatal error: Uncaught Error: Call to undefined function add_filter() in C:\xampp\htdocs\WAIT FOR DELETE\wp-content\plugins\jetpack\class.jetpack-twitter-cards.php:342 Stack trace: #0 C:\xampp\htdocs\WAIT FOR DELETE\wp-content\plugins\jetpack\class.jetpack-twitter-cards.php(352): Jetpack_Twitter_Cards::init() #1 {main} thrown in C:\xampp\htdocs\WAIT FOR DELETE\wp-content\plugins\jetpack\class.jetpack-twitter-cards.php on line 342