Just a quick tip. I installed the quickstart for EShop on Joomla5 and the site refused to load with error 500 in the front end and the following error (in admin)
missing class is declared in the file plugins/behaviour/compat/src/Extension/Compat.php
Locate the file administrator/cache/autoload_psr4.php and delete it. Access Joomla 4 again and the file will get recreated automatically. This file is a map to all PHP classes Joomla uses and it is created and maintained automatically.
This will fix your issues
The following user(s) said Thank You: Giang Dinh Truong
