Composer Autoload Error

Message: Class "ComposerAutoloadClassLoader" not found

File: /var/www/clients/client1/web24/web/libraries/vendor/composer/autoload_real.php
Line: 38

#0 /var/www/clients/client1/web24/web/libraries/vendor/autoload.php(25): ComposerAutoloaderInitb4730542e342b0e2e39d4cfb81f5be63::getLoader()
#1 /var/www/clients/client1/web24/web/libraries/bootstrap.php(42): require('...')
#2 /var/www/clients/client1/web24/web/includes/framework.php(1330): require_once('...')
#3 /var/www/clients/client1/web24/web/includes/app.php(29): require_once('...')
#4 /var/www/clients/client1/web24/web/index.php(26): require_once('...')
#5 {main}