Not found RVSiteBuilder CMS App in .:/opt/alt/php81/usr/share/pear:/opt/alt/php81/usr/share/php:/usr/share/pear:/usr/share/php

Please contact your provider with info:
1. RVSitebuilder CMS App have not install.
2. Not found vendor path.
3. Your PHP version not compatible, Our system require PHP 7.1+