This bundle requires PuMuKIT version 4 or higher
composer require teltek/pumukit-oai-bundle
if not, add this to config/bundles.php
Pumukit\OaiBundle\PumukitOaiBundle::class => ['all' => true]
Then execute the following commands
php bin/console cache:clear
php bin/console cache:clear --env=prod
php bin/console assets:install