I get a error when installing laravel or when I try updating composer. How do i resolve it?

I get this error "require(/var/www/html/data_security/bootstrap/../vendor/autoload.php): failed to open stream: No such file or directory in /var/www/html/data_security/bootstrap/autoload.php on line 17" when installing laravel or when I try updating composer. How do i resolve it ?

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