# 500 Internal Error during installation

**URL:** https://forum.mautic.org/t/500-internal-error-during-installation/17196
**Category:** Mautic 3 - Install/Upgrade Support
**Created:** [November 28, 2020, 2:26pm UTC](https://forum.mautic.org/t/500-internal-error-during-installation/17196 "2020-11-28T14:26:42Z")
**Posts on this page:** 1
**Page:** 1

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### Author: ![emkal](https://sea2.discourse-cdn.com/flex020/user_avatar/forum.mautic.org/emkal/32/3982_2.png) [@emkal](https://forum.mautic.org/u/emkal)
#### Post date: [November 28, 2020, 2:26pm UTC](https://forum.mautic.org/t/500-internal-error-during-installation/17196/1 "2020-11-28T14:26:42Z")

</div>

Installing Mautic 3  
_My PHP version is_ : 7.2  
_My MySQL/MariaDB version is_: 10.3.27

**Installing Errors**  
_I am_ (delete as applicable): Installing

_These errors are showing in the installer_ : 500 Internal Server Error

_These errors are showing in the Mautic log_ :

[27-Nov-2020 17:11:50 UTC] Symfony\Component\Debug\Exception\ClassNotFoundException: Attempted to load class “SimplifiedXmlDriver” from namespace “Doctrine\ORM\Mapping\Driver”.  
Did you forget a “use” statement for another namespace? - in file mautic/var/cache/prod/Container0xj6ape/appProdProjectContainer.php - at line 5887

**Your problem**

I am trying to install Mautic 3 on my Managed VPS server, and I am receiving error 500.

_Steps I have tried to fix the problem_ :

Checked the file and directories permissions and they are fine.