HTTP 500

Symptom: HTTP 500 on /install, login, or a CMS page.

Likely cause: missing .env / APP_KEY; storage/ or bootstrap/cache not writable; PHP version below 8.4; uncaught exception.

Check

1. storage/logs/laravel.log — first exception, not the last warning.
2. PHP version is 8.4 (CLI and FPM can differ).
3. Document root is backend/public.
4. storage/ and bootstrap/cache writable by the PHP user.

Fix

• Fix permissions (File permissions). Complete Composer.
• Never paste APP_KEY into public tickets. The installer generates it; do not invent one in docs.
• If the site already has an admin, /install returning 404 is correct — that is not a 500.

If only PDFs/mail fail but the CMS saves: that is the queue, not this 500.

Related: Installer.