Thanks for the tip, it worked for my sites which also had the problem :
Une erreur de type E_COMPILE_ERROR a été causée dans la ligne 59 du fichier /home/qyaolay/www/wp-content/plugins/backwpup/vendor/composer/autoload_real.php. Message d’erreur : require(): Failed opening required '/home/qyaolay/www/wp-content/plugins/backwpup/vendor/composer/../amphp/amp/lib/functions.php' (include_path='/home/qyaolay/www/wp-content/plugins/backwpup/vendor/pear/pear_exception:/home/qyaolay/www/wp-content/plugins/backwpup/vendor/pear/console_getopt:/home/qyaolay/www/wp-content/plugins/backwpup/vendor/pear/pear-core-minimal/src:/home/qyaolay/www/wp-content/plugins/backwpup/vendor/pear/archive_tar:.:/usr/local/php7.4/lib/php')
