I installed Magento2 successfully through the commandline, but when i try to access the website, i get a Server Error 500.

The server runs on Ubuntu 14.04

I have no idea what is wrong, or what i am doing wrong. I used a script to install Magento2 so i expect it to be correct

PHP Errors:

[Wed Mar 02 17:03:18.718890 2016] [:error] [pid 2292] [client] PHP Fatal error: Uncaught exception 'ReflectionException' with message 'Class Magento\Framework\App\ResourceConnection\Proxy does not exist' in /var/www/html/vendor/magento/framework/Code/Reader/ClassReader.php:19\nStack trace:\n#0 /var/www/html/vendor/magento/framework/Code/Reader/ClassReader.php(19): ReflectionClass->__construct('Magento\\Framewo...')\n#1 /var/www/html/vendor/magento/framework/ObjectManager/Definition/Runtime.php(44): Magento\Framework\Code\Reader\ClassReader->getConstructor('Magento\\Framewo...')\n#2 /var/www/html/vendor/magento/framework/ObjectManager/Factory/Dynamic/Developer.php(71): Magento\Framework\ObjectManager\Definition\Runtime->getParameters('Magento\\Framewo...')\n#3 /var/www/html/vendor/magento/framework/ObjectManager/ObjectManager.php(71): Magento\Framework\ObjectManager\Factory\Dynamic\Developer->create('Magento\\Framewo...')\n#4 /var/www/html/vendor/magento/framework/ObjectManager/Factory/AbstractFactory.php(236): Magento\Framework\ObjectManager\ObjectManager->get('Magento\\Framewo...')\n#5 /var/ww in /var/www/html/vendor/magento/framework/Code/Reader/ClassReader.php on line 19

and this multiple times

[Wed Mar 02 17:03:18.718739 2016] [:error] [pid 2292] [client] PHP Warning: include(): Failed opening '/var/www/html/var/generation/Magento/Framework/App/ResourceConnection/Proxy.php' for inclusion (include_path='/var/www/html/var/generation:/var/www/html/lib/internal:/var/www/html/var/generation:/var/www/html/lib/internal:/var/www/html/vendor/phpseclib/phpseclib/phpseclib:/var/www/html/vendor/magento/zendframework1/library:/var/www/html/vendor/phpunit/php-file-iterator:/var/www/html/vendor/phpunit/phpunit:/var/www/html/vendor/symfony/yaml:.:/usr/share/php:/usr/share/pear') in /var/www/html/vendor/magento/framework/Code/Generator/Io.php on line 158


[Wed Mar 02 17:03:18.718377 2016] [:error] [pid 2292] [client] PHP Warning: include(): Failed opening '/var/www/html/var/generation/Magento//Framework/App/ResourceConnection/Proxy.php' for inclusion (include_path='/var/www/html/var/generation:/var/www/html/lib/internal:/var/www/html/var/generation:/var/www/html/lib/internal:/var/www/html/vendor/phpseclib/phpseclib/phpseclib:/var/www/html/vendor/magento/zendframework1/library:/var/www/html/vendor/phpunit/php-file-iterator:/var/www/html/vendor/phpunit/phpunit:/var/www/html/vendor/symfony/yaml:.:/usr/share/php:/usr/share/pear') in /var/www/html/vendor/composer/ClassLoader.php on line 412

Also, this is the core_config_data from the magento database

enter image description here

Any idea what i could try?

chown -R www-data:www-data /var/www/magento2/ 
chmod 777 -R var
chmod 777 -R generated
chmod 777 -R app/etc
rm -rf var/cache/* var/page_cache/* var/generation/*


php bin/magento setup:di:compile;
  • worked for me and i had missing other class that wasn't mentioned Nov 11 '19 at 0:51
  • 17
    chmod 777 is a very bad idea and allows others to hack your server easily especially on shared hosting! fix the users instead
    – Black
    Jan 7 '20 at 13:54

Delete composer autoload (vendor/autoload.php) as suggested by @JELLEJ and type composer install in magento root folder to recreate it.

It worked for me on Magento 2.3.5-p1 (but should work in other versions).

  • I tried all the other suggestions on this page and this was the only one that worked for me. Thanks! Aug 6 '20 at 17:36
  • didn't work for other versions Aug 17 '20 at 11:29
  • 1
    The accepted answer is true, but this one too depending on the situation. Worked for me. Aug 25 '20 at 9:22
  • 1
    worked for me! thx!
    – Alex B
    Nov 17 '20 at 17:58

several classes in Magento2 are generated dynamically. Except you are in Developer mode, this does not happen automatically.

To activate the developer Mode, you have to uncomment the Line in the beginning of your .htaccess file.

For production and default mode you have to execute the command bin/magento setup:di:compile from your magento root to generate the classes

  • After installing Magento2, and using the command setup:di:compile I still get the Server Error 500, and i noticed that i cannot show or set modes in magento using the deploy:mode:show and deploy:mode:set command.
    – Maarten
    Mar 3 '16 at 13:06
  • @Maarten, check your server logs
    – Black
    Feb 19 '20 at 15:48
  • Sometimes for me it helps to delete the vendor/autoload.php file
    – JELLEJ
    May 18 '20 at 8:50
  • 1
    @black, I don't say it is not needed. I say sometimes it helps removing it and doing the composer install again.
    – JELLEJ
    Sep 28 '20 at 13:46

In case you are facing this issue whilst the permission set correctly already and mainly use RHEL/CentOS, you may be facing issues with files security context SElinux, as per the docs here, you may need to change the security context due to SElinux configuration on your root directory as following:


chcon -R --type httpd_sys_rw_content_t <magento_root>/app/etc


chcon -R --type httpd_sys_rw_content_t <magento_root>/var


chcon -R --type httpd_sys_rw_content_t <magento_root>/pub/media


chcon -R --type httpd_sys_rw_content_t <magento_root>/pub/static


chcon -R --type httpd_sys_rw_content_t <magento_root>/generated

This will make SElinux allow access from nginx/apache to your magento files.

  • First reason could be you have installed PHP 8 and Magento2 is not compatible with it yet. So to resolve this, you need to use PHP 7.4.
  • Other reason we need to find with below steps:
    • Open the bootstrap.php file present in the app folder of magento directory.
    • Remove # from the beginning of the line #ini_set(‘display_errors’, 1);
    • Save the file and refresh your browser to see the exact issue.

Happy Learning !! Thank You !!

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