Fix error on magento instalation

On server ubuntu 18, whit apache 2 and php 7.2. After install magento 2.3.4 from composer gettin erro 500 [login to view URL] the log said: [Sat Feb 22 20:37:34.050693 2020] [proxy_fcgi:error] [pid 29368] [client [login to view URL]] AH01071: Got error 'PHP message: PHP Fatal error: Uncaught ReflectionException: Class Magento\\Framework\\App\\ResourceConnection\\Proxy does not exist in /var/www/html/magento/vendor/magento/framework/Code/Reader/[login to view URL]\nStack trace:\n#0 /var/www/html/magento/vendor/magento/framework/Code/Reader/[login to view URL](26): ReflectionClass->__construct('Magento\\\\Framewo...')\n#1 /var/www/html/magento/vendor/magento/framework/ObjectManager/Definition/[login to view URL](54): Magento\\Framework\\Code\\Reader\\ClassReader->getConstructor('Magento\\\\Framewo...')\n#2 /var/www/html/magento/vendor/magento/framework/ObjectManager/Factory/Dynamic/[login to view URL](48): Magento\\Framework\\ObjectManager\\Definition\\Runtime->getParameters('Magento\\\\Framewo...')\n#3 /var/www/html/magento/vendor/magento/framework/ObjectManager/[login to view URL](70): Magento\\Framework\\ObjectManager\\Factory\\Dynamic\\Developer->create('Magento\\\\Framewo...')\n#4 /var/www/html/magento/vendor/magento/framework/ObjectManager/Factory/[login to view URL](167): Magento\\Framework\\ObjectMan...\n' if u really really now how to fix... PVme.. I think this erro is simple for who know about it!