Next.js 15 Build Succeeds but Deployment Fails with "Unexpected Error"

Hi Vercel Team,

I’m on the Hobby plan and deploying a Next.js 15 project using pnpm and Prisma with Supabase as the backend. Problem:

next build completes successfully
Static pages and serverless functions are generated
Deployment ends with:

An unexpected error happened when running this build. We have been notified of the problem.

1Build Details:23Framework: Next.js 15.4.445Package manager: pnpm67Database: Prisma + Supabase89Node.js version: 22.x (also tried 20.x)1011Postinstall: prisma generate (works fine)1213Relevant Logs:14[08:08:38.720] Route (app) ...  ✓ Generating static pages (31/31)15[08:08:39.405] Created all serverless functions16[08:08:39.684] Build Completed in /vercel/output17[08:08:39.803] Deploying outputs...18[08:08:46.023] An unexpected error happened when running this build.1920What I’ve tried:2122Locked Node version to 20.x in package.json2324Verified local production build works (pnpm build && pnpm start)2526Confirmed environment variables are correctly set for Supabase and Prisma2728It seems like a deployment-stage issue since the Next.js build completes without errors.2930Can you please help check what could be causing the unexpected error during final deployment?3132Thank you!

Hi Vercel Team,

I’m on the Hobby plan and deploying a Next.js 15 project using pnpm and Prisma with Supabase as the backend. Problem:

next build completes successfully
Static pages and serverless functions are generated
Deployment ends with:

An unexpected error happened when running this build. We have been notified of the problem.

1Build Details:23Framework: Next.js 15.4.445Package manager: pnpm67Database: Prisma + Supabase89Node.js version: 22.x (also tried 20.x)1011Postinstall: prisma generate (works fine)1213Relevant Logs:14[08:08:38.720] Route (app) ...  ✓ Generating static pages (31/31)15[08:08:39.405] Created all serverless functions16[08:08:39.684] Build Completed in /vercel/output17[08:08:39.803] Deploying outputs...18[08:08:46.023] An unexpected error happened when running this build.1920What I’ve tried:2122Locked Node version to 20.x in package.json2324Verified local production build works (pnpm build && pnpm start)2526Confirmed environment variables are correctly set for Supabase and Prisma2728It seems like a deployment-stage issue since the Next.js build completes without errors.2930Can you please help check what could be causing the unexpected error during final deployment?3132Thank you!