Fix Website Backend Server Errors

I need a developer to FIX a deployment bug on a Vercel-hosted website.

IMPORTANT RULES:
1. You will NOT receive repository download access
2. You will NOT clone or export source code
3. Work is limited to debugging + configuration only
4. Screen-share or recorded steps are required

STACK:
- Frontend: React
- Hosting: Vercel
- Backend: separate API (already working)

TASKS:
- Identify why the Vercel deployment is failing
- Fix environment variable / build / routing issue
- Confirm site loads correctly

ACCESS PROVIDED:
- Read-only GitHub access OR
- Vercel dashboard collaborator (NO repo download)
- Logs, error screenshots, build output

DELIVERABLE:
- Website working on Vercel
- Written explanation of what was fixed

If you ask for full repo download or ZIP files, I will immediately end the contract.