Generic yet obscure Vinxi error when compiling

┌──────────────────────────────────────┐
│ 📦 Compiling server-fns router...    │
└──────────────────────────────────────┘
vinxi building router server-fns in http mode
vite v5.3.3 building SSR bundle for production...
✓ 0 modules transformed.
x Build failed in 53ms

 ERROR  Could not resolve entry module "$vinxi/handler/server-fns".                                                      14:13:17  

  at getRollupError (/C:/projects/polandballworld/node_modules/rollup/dist/es/shared/parseAst.js:392:41)
  at error (/C:/projects/polandballworld/node_modules/rollup/dist/es/shared/parseAst.js:388:42)
  at ModuleLoader.loadEntryModule (/C:/projects/polandballworld/node_modules/rollup/dist/es/shared/node-entry.js:19092:20)
  at async Promise.all (index 0)



 ERROR  Could not resolve entry module "$vinxi/handler/server-fns".                                                      14:13:17