From the moment I add WP Smush Pro to my website I get

From the moment I add WP Smush Pro to my website I get the error "Fatal error: Class 'WP_Http' not found in /Users/warre/MEGA/__Twist/__projects/Hotel Recour/3. Wordpress development/Live/wp-includes/http.php on line 28"

This doesn't happen with the WP SMUSH plugin (first encounter of WP Smush Pro is not very positive in this way sadly)