Symfony Re-Install & DB Fix

I have an earlier Symfony build that needs to be redeployed on a fresh server, but the moment the container spins up the application throws database connection errors. Your first job is to get that previous build fully installed (Composer install, env configuration, cache clear, migrate) and then eliminate the connection problem so the app can read and write data normally again.

Key points you’ll tackle:
• Treat this strictly as a bug-fix pass focused on database interactions; the codebase itself stays as is.
• Diagnose why the connection fails (credentials, DSN syntax, driver or version mismatch, network/firewall rules, etc.) and apply whatever configuration or minimal code tweak is required.
• Prove the fix by running any existing doctrine:migrations, seeding dummy data, and showing CRUD endpoints or a simple repository call working without error.

Timeframe is tight: I need the site up within 24 hours of project acceptance. I’ll be online to provide repo access, database details, and server credentials immediately. A quick, clean fix on this task will open the door to a series of follow-up improvements I have queued.