We have an unresolved protected Preview publication failure on a Pro project. The latest application deployment reports build state READY but deployment state ERROR, errorCode patch_build_5xx, and errorMessage null. The dashboard says: The deployment failed because of an internal Vercel error.
Minimal build excerpt: Vercel CLI 62.7.0 Using Python 3.12 Build Completed in /vercel/output [25s] Deploying outputs...
The application uses Build Output API v3 with 11 Python functions, @vercel/python 13.0.4, and @vercel/build-utils 14.9.3. Following the support assistant's suggestion, we made every function self-contained: all runtime files are physically inside its .func directory and no filePathMap or external file references remain. Local relocation and byte verification passed. The separately authorized hosted attempt still failed at publication. We have no provider trace, so the root cause remains unknown.
The private support assistant refuses a human case because the returned code is not an uppercase INTERNAL_ code or the exact message Your Team encountered an unknown problem. It says this is an internal intake rule, not a clause in the public Support Terms. The documented Support Center case controls are unavailable; the project case list is empty.
Could Vercel staff help establish a private case or identify the supported escalation route, and inspect the provider-side patchBuild failure? We can provide the exact deployment/build identifiers privately to verified Vercel staff through an official channel. Since preparing this report, the separately authorized minimal native Python-builder diagnostic has published successfully as a protected Preview on the same project. It contains no application code or database credentials and uses no custom serializer. This demonstrates publication of that minimal function; it does not establish the cause of the application failure. Endpoint execution is not yet verified.
We are preserving Preview protection and existing project settings. This is a non-production deployment blocker; we are not claiming a platform-wide outage. This public report intentionally excludes project/team/deployment identifiers, Preview URLs, credentials, database URLs, environment values, application source, and full logs.