# Error on Install

**URL:** <https://forum.mautic.org/t/error-on-install/24081>\
**Category:** Mautic 4 Install/Upgrade Support\
**Created:** [May 12, 2022, 9:44pm UTC](https://forum.mautic.org/t/error-on-install/24081 "2022-05-12T21:44:25Z")\
**Posts on this page:** 1\
**Page:** 1

<div class="post-metadata">

**Author:** ![ojaneri](https://sea2.discourse-cdn.com/flex020/user_avatar/forum.mautic.org/ojaneri/32/1921_2.png) [@ojaneri](https://forum.mautic.org/u/ojaneri)\
**Post date:** [May 12, 2022, 9:44pm UTC](https://forum.mautic.org/t/error-on-install/24081/1 "2022-05-12T21:44:25Z")

</div>

**Your software** Mautic 4  
_My PHP version is_ : 7.4

Trying to access via browser I get a 500 error.  
No logs on mautic, on apache2 logs it shows:  
[Thu May 12 18:35:29.513982 2022] [proxy\_fcgi:error] [pid 15381:tid 140692105910016] [client 127.0.0.1:58496] AH01071: Got error ‘PHP message: PHP Fatal error: Uncaught Error: Class ‘Mautic\CoreBundle\ErrorHandler\ErrorHandler’ not found in /var/www/html/janeri/mautic/index.php:22\nStack trace:\n#0 {main}\n thrown in /var/www/html/janeri/mautic/index.php on line 22’

When trying to upadte, I got the error

php bin/console mautic:update:apply

PHP Fatal error: Uncaught Error: Class ‘Mautic\CoreBundle\Release\ThisRelease’ not found in /var/www/html/janeri/mautic/app/AppKernel.php:47  
Stack trace:  
#0 /var/www/html/janeri/mautic/bin/console(39): AppKernel-\>\_\_construct()  
#1 {main}  
thrown in /var/www/html/janeri/mautic/app/AppKernel.php on line 47

Tried to install from fresh the 4 version, but no success.

Can anyone help? Thanks!