The website was working. Now it says “500 Internal Server Error” and nothing else.
The message is deliberately vague — the server doesn’t reveal details, for security reasons. But the cause is almost always one of four things.
First: switch on error logging
Without this you are searching blind. In wp-config.php, before the line “That's all”:
define('WP_DEBUG', true);
define('WP_DEBUG_LOG', true);
define('WP_DEBUG_DISPLAY', false);
Refresh the page, then look in wp-content/debug.log. It says exactly which file and which line.
Don’t forget to switch it off when you are done.
1. A plugin or theme (the most common)
Usually right after an update or an installation.
If you can’t get into the admin: over FTP or in File Manager, rename the wp-content/plugins folder to plugins-off. That deactivates them all.
If the website comes back — a plugin is to blame. Restore the folder name, then deactivate them one at a time until you find it.
The same goes for the theme: rename its folder and WordPress falls back to a default theme.
2. A broken .htaccess
Rename it to .htaccess-old and refresh.
If that works — that is where the problem was. Go to Settings → Permalinks and just click Save; WordPress will create a new, clean one.
3. Not enough memory
In wp-config.php:
define('WP_MEMORY_LIMIT', '256M');
If that helps, some plugin is using more than it should. The fix is temporary — find out which one it is.
4. Wrong file permissions
Folders should be 755, files 644. If someone set 777 “to make it work”, some servers refuse that for security reasons.
In File Manager: select everything, Permissions, apply recursively.
If nothing helps
Ask your host to look at the server error log. It shows more than you can see, and support can check it in a minute.
With us, that is part of support — we don’t charge for reading a log.
How to keep it from happening again
Run updates on a staging copy first, take a backup before every bigger change, and don’t install a plugin that hasn’t been updated in over a year.
NVMe hosting with free SSL, daily backups and support that actually answers.
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