Flarum shows HTTP ERROR 500 after update

DataSense

The issue

Hi everyone,
I’m hoping someone here can help me.

I recently tried to update my Flarum installation, but after the update finished, my site is now showing “HTTP ERROR 500” and I can’t access the forum at all.

Before the update, everything was working fine. I haven’t changed anything else manually since then. I’m not sure whether this is caused by an extension, Composer, or a server/PHP issue.

If anyone has experienced this before or knows where I should start checking (logs, commands to run, files to look at), I’d really appreciate your help.

Thanks in advance!

Flarum information

Flarum core: 1.8.11
PHP version: 8.3.28
MySQL version: 10.11.15-MariaDB-ubu2204
Loaded extensions: Core, date, libxml, openssl, pcre, zlib, filter, hash, json, pcntl, random, Reflection, SPL, session, standard, sodium, mysqlnd, PDO, xml, bcmath, bz2, calendar, ctype, curl, dom, mbstring, FFI, fileinfo, ftp, gd, gettext, iconv, imagick, imap, intl, ldap, exif, mysqli, pdo_mysql, Phar, posix, pspell, readline, shmop, SimpleXML, soap, sockets, sysvmsg, sysvsem, sysvshm, tokenizer, xmlreader, xmlwriter, xsl, zip, Zend OPcache
+--------------------------+---------+--------+
| Flarum Extensions        |         |        |
+--------------------------+---------+--------+
| ID                       | Version | Commit |
+--------------------------+---------+--------+
| flarum-tags              | v1.8.5  |        |
| flarum-flags             | v1.8.2  |        |
| flarum-suspend           | v1.8.4  |        |
| v17development-seo       | v2.0.9  |        |
| flarum-approval          | v1.8.2  |        |
| fof-user-bio             | 1.4.2   |        |
| fof-upload               | 1.8.7   |        |
| fof-split                | 1.1.1   |        |
| fof-sitemap              | 2.4.1   |        |
| fof-reactions            | 1.4.1   |        |
| fof-moderator-notes      | 1.3.0   |        |
| fof-links                | 1.4.0   |        |
| fof-best-answer          | 1.6.5   |        |
| flarum-subscriptions     | v1.8.1  |        |
| flarum-sticky            | v1.8.2  |        |
| flarum-statistics        | v1.8.1  |        |
| flarum-pusher            | v1.8.1  |        |
| flarum-nicknames         | v1.8.2  |        |
| flarum-mentions          | v1.8.5  |        |
| flarum-markdown          | v1.8.1  |        |
| flarum-lock              | v1.8.2  |        |
| flarum-likes             | v1.8.1  |        |
| flarum-lang-english      | v1.8.0  |        |
| flarum-extension-manager | v1.0.7  |        |
| flarum-emoji             | v1.8.1  |        |
| flarum-bbcode            | v1.8.0  |        |
+--------------------------+---------+--------+
Base URL: https://[example.com]
Installation path: /home/[user]/web/[example.com]/public_html
Queue driver: sync
Session driver: file
Scheduler status: Never run
Mail driver: smtp
Debug mode: off

huseyinfiliz

DataSense It’s hard to say anything without sharing the server/Apache or Laravel logs. Maybe the issue has just appeared because Flarum’s cache was cleared, or because something was updated in the background on your server.

luceos

Check https://docs.flarum.org/troubleshoot on how to identify common issues, the reason for your error is likely to be found in the logs of either Flarum or the webserver.

DataSense

huseyinfiliz I installed Flarum using HestiaCP, and I do have shell (SSH) access to the server. I’m quite new to Flarum, so I’d really appreciate a step-by-step guide on how to troubleshoot or fix this issue. Please assume beginner level if possible.

huseyinfiliz

DataSense HTTP 500 errors are generally not caused by Flarum itself. For this reason, you should check your Nginx/Apache logs. Of course, you should also take a look at the laravel.log file located in the storage directory.

In your server management panel, there is a page called “Logs.” You should be able to see the cause of the problem there.

DataSense

luceos

~/web/[example.com]/public_html$ php flarum cache:clear
PHP Warning:  require(/home/datasense/web/[example.com]/public_html/vendor/autoload.php): Failed to open stream: No such file or directory in /home/datasense/web/[example.com]/public_html/site.php on line 22
PHP Fatal error:  Uncaught Error: Failed opening required '/home/datasense/web/[example.com]/public_html/vendor/autoload.php' (include_path='.:/usr/share/php') in /home/datasense/web/[example.com]/public_html/site.php:22
Stack trace:
#0 /home/datasense/web/[example.com]/public_html/flarum(11): require()
#1 {main}
  thrown in /home/datasense/web/[example.com]/public_html/site.php on line 22

huseyinfiliz

DataSense This error already tells us something important.

vendor/autoload.php is missing or not accessible. This file is required for Flarum to run, and if it’s not there, PHP throws a fatal error, which results in an HTTP 500 error.

So this is not a cache issue and Flarum isn’t even starting properly. Most likely:

vendor/ was deleted or never installed
Composer was not run
The site was moved or updated incompletely

You should run composer install in the Flarum root directory to restore the vendor folder.
After that, php flarum cache:clear should work.

Server logs are still useful, but in this case the main problem is clearly the missing vendor/autoload.php.

Run thish command:
composer install --no-dev -o
or
php composer.phar install --no-dev -o

DataSense

huseyinfiliz Thank you for the clear explanation, that really helped.

You were right, the vendor/autoload.php file was missing. I ran:

composer install --no-dev -o

from the Flarum root directory, and after that:

php flarum cache:clear

Everything is working again now and the forum is back online.

Really appreciate your help and guidance.