Zend certified PHP/Magento developer

Warning: require(vendor/autoload.php): Failed to open stream: No such file or directory in

Below is the error I get in store frontend.

Warning: require(vendor/autoload.php): Failed to open stream: No such file or directory in /home/magento/web/mymagentostorename.com/public_html/poms/libs/phpfastcache_config.php

On running composer update and composer install, I find the installation failure messages for several modules. Could you please share some insights or possible solutions to the issue?

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