This article provides a solution for the Reflection Exception error, during installation.
During the installation, a message similar to the following displays:
[ERROR] exception 'ReflectionException' with message 'Class Magento\Framework\StoreManagerInterface does not exist' in /<path>/lib/internal/Magento/Framework/Code/Reader/ClassReader.php
Clear all directories and files under Magento's
var subdirectory and install the Magento software again.
As the Magento file system owner or as a user with
root privileges, enter the following commands:
$ cd <your Magento install directory>/var
$ rm -rf var/cache/* di/* generation/* page_cache/*
If you use Redis and still get an error, clear the Redis cache as follows:
$ redis-cli FLUSHALL